EP2206498B9 - Mixed ORL1/[mu] agonists for treating pain - Google Patents

Abstract

Use of compounds (I), which exhibit an affinity for the mu -opioid-receptor of at least 100 nM (K i value for human) and an affinity for opioid receptor-like (ORL)-1-receptor, is claimed, where the ratio of the affinities ORL1/mu defined as 1/[K i(ORL1)/K i(mu )] is 1:10 to 30:1, for the production of a medicament and to treat: diabetic neuropathy; narcosis or analgesia during narcosis; pain in patients over 60 years and in patients with increased addictive potential and postoperative pain. An independent claim is included for use of a mu -agonist (II), which is selective as an ORL1/mu defined as 1/[K i(ORL1)/K i(mu )] 1:10, and a ORL1-agonist, which is selective as ORL1/mu defined as 1/[K i(ORL1)/K i(mu )] in a ratio of 30:1 in a mixture, which exhibits the characteristics of the compounds, for the manufacture of medicaments to treat pain. ACTIVITY : Neuroprotective; Analgesic. MECHANISM OF ACTION : Opioid receptor-like-1/mu -agonist.

Description

In addition to acute pain, which is of limited duration and usually disappears rapidly after elimination of the triggering stimuli, chronic pain in particular poses a medical challenge. Acute pain events by stimulation of intact nociceptors have an important role to play in preserving body integrity. The subsequent reactions for pain prevention protect against damage. Chronic pain has lost this protective function. There is a pain disorder. Chronic pain can be divided into two major groups. The pathophysiological nociceptor pain is caused by tissue trauma caused by the excitation of intact nociceptors. These include in particular chronic inflammatory pain. In contrast, pain caused by damage to nerves themselves is called neuropathic pain.

The transition from acute pain to chronic pain can occur within hours. This affects, for example, the pain treatment during and after surgery. Although the treatment of acute pain is of great importance today in the minds of physicians, the treatment of postoperative pain is subject to severe limitations ( Power, Brit. J. Anaesth., 2005, 95, 43-51 ). Acute pain may be chronic following pathophysiological processes peripherally and in the CNS following tissue damage such as surgery. The association between tissue damage, acute postoperative pain, and developing chronic pain has been well studied, and the severity of acute pain can be considered as a predictive factor for the duration of chronic pain ( Power, Brit. J. Anaesth., 2005, 95, 43-51 ). For this reason alone, a satisfactory treatment of acute pain is essential.

A problem in the fight against acute pain are the side effects of the acute pain in highly effective μ-opioids such as morphine or fentanyl, especially respiratory depression. Since this side effect occasionally leads to fatalities in freshly operated patients, in many cases the drugs are not given in sufficient quantity to satisfactorily combat the pain. On the other hand, treatment of postoperative pain without opioids is unimaginable today. The fear of respiratory depression and other typical side effects of μ-opioid, however, often leads to inadequate use of opioids in severe pain, for example in cancer patients ( Davis et al, Respiratory Care Journal 1999, 44 (1 )). Furthermore, the risk of respiratory depression after administration of opioids is increased in the elderly compared to younger people. In fact, the risk of developing respiratory depression increases significantly in people over the age of 60 ( Cepeda et al, Clinical Pharmacology and Therapeutics 2003, 74, 102-112 ). There is therefore an urgent need for new drugs for the treatment of pain in which respiratory depression is reduced.

However, as already mentioned, the treatment of chronic pain poses a greater challenge, as the drugs on the market are sometimes highly effective in acute pain, but in many cases they do not provide satisfactory pain relief in chronic pain.

inflammatory pain

Pain, in addition to redness, swelling, overheating and impaired function, is one of the five cardinal symptoms of inflammation. Inflammatory processes are among the most important mechanisms of pain development. The typical inflammatory pains are triggered by the release of bradykinin, histamine and prostaglandins with acidification of the tissue and exudate pressure on the nociceptors. Nociception, unlike other sensations, is not subject to habituation. Rather, previous pain impulses can increase the processing of subsequent stimuli in the sense of sensitization. If, for example, long-term activation of nociceptors in the inflamed tissue leads to an increased influx of pain impulses into the central nervous system, lasting effects occur Sensitization phenomena at the central synapses. These central sensitization phenomena are expressed in the increase in spontaneous activity and in stronger responses of central neurons whose receptive fields are also increasing ( Coderre et al., Pain 1993, 52, 259-285 ). These changes in the response of central neurons may contribute to spontaneous pain and hyperalgesia (increased pain sensation to a noxious stimulus) typical of inflamed tissue ( Yaksh et al., PNAS 1999, 96, 7680-7686 ).

One of the most important processes in inflammation is the appearance of arachidonic acid metabolites. These compounds do not directly activate nociceptors, but reduce the stimulus transmission threshold of the C fibers and sensitize them to other stimuli. In particular, non-steroidal anti-inflammatory drugs (NSAIDs) have proven to be effective in the treatment of inflammatory pain since they block the breakdown of arachidonic acid ( Dickensen, A., International Congress and Symposium Series - Royal Society of Medicine (2000), 246, 47-54 ). However, their use in the long-term treatment of chronic pain is limited by sometimes significant adverse effects, such as gastroenteric ulcers or toxic kidney damage.

However, in the treatment of inflammatory pain, the inhibitory control of stimulus transmission is important. μ-opioids are the most important representatives of this class. Chronic pancreatitis, for example, is associated with pain, which is one of the clinically most difficult to treat pain conditions. The administration of NSAIDs may reduce the pain only slightly, but because of the increased risk of bleeding leads to an excessive risk. The next step is generally the treatment with μ-opioids. Dependence on narcotics is widespread among affected persons ( Vercauteren et al., Acta Anesthesiologica Belglca 1994, 45, 99-105 ). There is therefore an urgent need for compounds which are very effective in inflammatory pain and have a reduced dependence potential.

Neuropathic pain

Neuropathic pain occurs when peripheral nerves are damaged in a mechanical, metabolic or inflammatory manner. The occurring Pain pictures are mainly characterized by the appearance of spontaneous pain, hyperalgesia and allodynia (pain is already triggered by non-noxious stimuli). As a consequence of the lesions, there is an increased expression of Na + cells and thus spontaneous activity in the damaged axons and their neighboring axons ( England et al., Neurology 1996, 47, 272-276 ). The excitability of the neurons is increased and they respond to incoming stimuli with an increased discharge frequency. The result is increased sensitivity to pain, which contributes to the development of hyperalgesia and spontaneous pain ( Baron, Clin. J. Pain 2000; 16 (2 Suppl), 12-20 ).

The causes and manifestations and therefore the treatment requirements of neuropathic pain are manifold. They arise as a result of injuries or diseases of the brain, spinal cord or peripheral nerves. Causes can be operations, eg. As phantom pain after amputation, strokes, multiple sclerosis, spinal cord injury, alcohol or drug abuse or other toxins, cancer but also metabolic diseases such as diabetes, gout, renal insufficiency or cirrhosis, or infectious diseases such as mononucleosis, ehrlichiosis, typhus, diphtheria, HIV, lues or Borrelia. The pain experience has very different signs and symptoms that can vary in number and intensity over time. Paradoxically, patients with neuropathic pain describe a decrease or disturbance of acute pain perception with a concomitant increase in neuropathic pain. The typical symptoms of neuropathic pain are described as tingling, burning, shooting, electrifying or radiating.

The basic pharmacological therapy for neuropathic pain includes tricyclic antidepressants and anticonvulsants used as monotherapy or in combination with opioids. These drugs usually only provide a certain pain relief, while freedom from pain is often not achieved. The frequently occurring side effects are often in the way of dose increases of the drugs to achieve adequate pain relief. In fact, for the satisfactory treatment of neuropathic pain, a higher dose of a μ-opioid is often needed than for the treatment of acute pain, whereby the side effects become even more significant. By the entry of μ-opioid typical Tolerance development and the consequent need for dose escalation further aggravates this problem. In summary, it can be stated that neuropathic pain is difficult to treat today and is only partially alleviated by high doses of μ-opioids ( Saudi Pharm. J. 2002, 10 (3), 73-85 ). There is therefore an urgent need for drugs for the treatment of chronic pain, the dose of which must not be increased until the occurrence of intolerable side effects in order to ensure a satisfactory pain therapy.

In recent decades, various other principles of action have been proposed and implemented for the treatment of chronic pain that do not have the typical opioid side effects. Thus, in the therapy of moderate to severe chronic pain, for example, antidepressants are used, which also have an analgesic effect in addition to the mood-enhancing effect. So far, however, no active principle could displace the μ-opioids from the central importance in pain therapy. One of the main reasons is the unprecedented potency of μ-opioids. In addition to respiratory depression, however, μ-opioids also have other disadvantages:

a) Opioid Induced Hyperalgesia

For over 100 years, it has been known that increased pain perception is one of the symptoms of opioid withdrawal. Today, the occurrence of pain symptoms is one of the criteria for the diagnosis of opioid withdrawal ( Angst et al, Anesthesiology 2006, 104, 570-587 ). A growing body of animal and human studies has shown that under certain circumstances, μ-opioids may cause changes in pain sensation that lead to hyperalgesia (sensation of increased pain intensity after painful stimulus). These studies show that the phenomenon of opioid-induced hyperalgesia occurs in both short-term and chronic opioid administration ( Pud et al, Drug and Alcohol Dependence 2006, 218-223 ). It is known, for example, that patients receiving anesthesia with a high proportion of opioids require about three times more opioids postoperatively compared to patients with hypnotic anesthesia. This marked effect also restricts the safe use of the μ-opioids, as the side effects such as respiratory depression, which increase the dose required for this purpose received greater importance. However, since the treatment of severe pain without opioids is not conceivable today, there is an urgent need for drugs that do not already lead by itself to increased pain intensity in the patient.

b) dependency potential

The μ-opioids used for pain therapy, such as morphine and fentanyl, have a dependency potential. In many cases withdrawal symptoms occur when these medicines are discontinued. This side effect of μ-opioids significantly limits the usefulness of these highly effective pain therapeutics because of fear of dependence μ-opioids are often not prescribed or taken in severe pain. There is therefore an urgent need for pain therapeutics which are highly effective and at the same time have a reduced potential for dependence in comparison with μ-opioids.

The typical side effects of μ-opioids are not equally strong in all patients. There are groups of patients for whom side effects are tolerable and others for whom they are a major problem. On average, however, the side effects are a problem that has not yet been resolved, although μ-opioids, originally used as a natural extract of opium, have long been used to treat pain. The first attempts to synthesize a morphine derivative without dependence potential were already made in 1874. However, it was found that the resulting substance - heroin - did not have an improved side effect profile compared to morphine. To date, numerous other attempts have been made to produce potent analgesics with improved side effect profile. Thus, oxycodone was synthesized in 1925, methadone in 1946, fentanyl in 1961, and tilidine in 1965. However, it turned out that a significant reduction in side effects is associated with a significant reduction in efficacy. The μ-typical side effects are well studied; they are antagonistic with the μ-antagonist naloxone and thus belong to the profile of action of μ-opioids. To date, there are no medicines that have the same potency as clinically used stage 3 μ-opioids (WHO schedule) such as fentanyl, sufentanil, morphine, oxycodone, Buprenorphine and hydromorphone, and at the same time have a significantly reduced side effect profile.

In summary, it can be said that the therapy of moderate to severe pain, both acute and chronic pain, despite all its disadvantages to a large extent based on the use of μ-opioids. This results mainly from the high potency of these compounds. However, the night falls are so significant that many patients, for their own reasons as well as the doctor's concerns, do not receive the necessary therapy for fear of side effects. There is therefore an urgent need for novel pain therapeutics which are based on an active principle, which on the one hand brings the high efficacy of μ-opioids, the disadvantages such as dependence, increased pain sensation, respiratory depression and decreased effectiveness in chronic pain, however.

The object of the present invention was therefore to find an active principle for medicaments, whereby medicaments which act according to this principle bring along the high efficacy of the .mu.-opioids, the disadvantages such as dependency, respiratory depression and diminished efficacy in chronic pain, however Have opioids to a reduced extent.

The object is solved by the present invention.

• zur Anwendung bei einer Narkose;
• zur Anwendung bei der narkosebegleitenden Behandlung von Schmerz;
• zur Anwendung bei der Behandlung von neuropathischem Schmerz ausgewählt aus der Gruppe bestehend aus chronischem neuropathischem Schmerz, polyneuropathischem Schmerz und Cytostatika-induziertem Polyneuropathleschmerz.

The invention relates to the use of mixed ORL1 / μ agonists according to formula (I), which have an affinity for μ-opioid receptor of at least 100 nM (K _i value human) and an affinity for the human ORL-1 receptor wherein the ratio between the affinities ORL1 / μ defined as 1 / [K _{t (ORL1)} / K _{t (μ)} ] is between 0.1 and 30,

• for use in anesthesia;
• for use in the anesthetic treatment of pain;
• for use in the treatment of neuropathic pain selected from the group consisting of chronic neuropathic pain, polyneuropathic pain, and cytostatic-induced polyneuropathic pain.

worin
R¹ und R² unabhängig voneinander für H oder CH₃ stehen, wobei R¹ und R² nicht gleichzeitig H bedeuten;
R³ für Phenyl, Benzyl oder Heteroaryl jeweils unsubstituiert oder einfach oder mehrfach mit F, Cl, OH, CN oder OCH₃ substituiert, steht;
W für NR⁴. O oder S steht; wobei
R⁴ für H; C_1-5-Alkyl Phenyl: über eine C_1-3-Alkyl-Gruppe gebundenes Phenyl, COR¹²; SO₂R¹² steht,
R¹² H; C_1-7-Alkyl, verzweigt oder unverzweigt, gesättigt oder ungesättigt, unsubstituiert oder einfach oder mehrfach mit OH, F oder COOC_1-4-Alkyl substituiert; C_4-6-Cycloalkyl; Aryl-, oder Heteroaryl, unsubstituiert oder einfach oder mehrfach mit F, Cl, Br, CF₃, OCH₃, C_1-4-Alkyl, verzweigt oder unverzweigt, unsubstituiert oder substituiert mit F, Cl, CN, CF₃, OCH₃ oder OH: oder über gesättigtes oder ungesättigtes C_1-3-Alkyl gebundenes Phenyl oder Heteroaryl, unsubstituiert oder einfach oder mehrfach mit F, Cl, Br, CF₃, OCH₃, C_1-4-Alkyl, verzweigt oder unverzweigt, unsubstituiert oder substituiert mit F, Cl, CN, CF₃, OCH₃ oder OH substituiert; oder über gesättigtes oder ungesättigtes C_1-3-Alkyl gebundenes C_5-6-Cycloalkyl; OR¹³; NR¹⁴R¹⁵ bedeutet;
R⁶ für H; COOR¹³, CONR¹³. OR¹³; C_1-5-Alkyl, gesättigt oder ungesättigt, verzweigt oder unverzweigt, unsubstituiert oder einfach oder mehrfach mit OH, F, CF₃ oder CN substituiert, steht;
R⁶ für H steht;
oder R⁵ und R⁶ gemeinsam (CH₂)_n mit n = 2, 3, 4, 5 oder 6 bedeuten, wobei einzelne Wasserstoffatome auch durch F, Cl, NO₂, CF₃, OR¹³, CN oder C₁-₅-Alkyl ersetzt sein können;
R⁷, R⁸, R⁹ und R¹⁰ unabhängig voneinander für H, F, Cl, Br, NO₂, CF₃, OH, OCH₃, CN, COOR¹³, NR¹⁴R¹⁵; C_1-5-Alkyl, Heteroaryl, unsubstituiert oder einfach oder mehrfach mit Benzyl, CH₃, Cl, F, OCH₃ oder OH substituiert, stehen;
wobei R¹³ H oder C_1-5-Alkyl bedeutet;
R¹⁴ und R¹⁵ unabhängig voneinander H oder C_1-5-Alkyl bedeuten;
X für O, S, SO, SO₂ oder NR¹⁷ steht;
R¹⁷ für H; C_1-5-Alkyl, gesättigt oder ungesättigt, verzweigt oder unverzweigt; COR¹² oder SO₂R¹² steht;
in Form ihrer reinen Diastereomeren, ihrer Racemate, ihrer reinen Enantiomeren, oder in Form von Mischungen der Stereoisomeren in einem bellebigen Mischungsverhältnis; als Basen oder in Form ihrer Salze, insbesondere der physiologisch verträglichen Salze oder Salze physiologisch verträglicher Säuren oder Kationen.Mixed ORL1 / μ agonists according to the invention are spirocyclic cyclohexane derivatives of the general formula (I):

wherein
R ¹ and R ^{2 are} independently H or CH ₃ , wherein R ¹ and R ^{2 are} not H at the same time;
R ^{3 represents} phenyl, benzyl or heteroaryl in each case unsubstituted or monosubstituted or polysubstituted by F, Cl, OH, CN or OCH ₃ ;
W for NR ⁴ . O or S is; in which
R ⁴ for H; C _1-5 alkyl phenyl: phenyl bonded via a C _1-3 alkyl group, COR ¹² ; SO ₂ R ¹² is
R ¹² H; C _1-7 -alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or poly-substituted by OH, F or COOC _1-4 -alkyl; C _4-6 cycloalkyl; Aryl or heteroaryl, unsubstituted or mono- or polysubstituted by F, Cl, Br, CF ₃ , OCH ₃ , C _1-4 alkyl, branched or unbranched, unsubstituted or substituted by F, Cl, CN, CF ₃ , OCH ₃ or OH: or phenyl which is bonded via saturated or unsaturated C _1-3 -alkyl or heteroaryl, unsubstituted or mono- or polysubstituted by F, Cl, Br, CF ₃ , OCH ₃ , C _1-4 -alkyl, branched or unbranched, unsubstituted or substituted with F, Cl, CN, CF ₃ , OCH ₃ or OH; or C _5-6 -cycloalkyl bonded via saturated or unsaturated C _1-3 -alkyl; OR ¹³ ; NR ¹⁴ R ¹⁵ means;
R ⁶ for H; COOR ¹³ , CONR ¹³ . OR ¹³ ; C _1-5 alkyl, saturated or unsaturated, branched or unbranched, unsubstituted or monosubstituted or polysubstituted by OH, F, CF ₃ or CN;
R ^{6 is} H;
or R ⁵ and R ⁶ together ^form (CH _{2) n} with n = 2, 3, 4, 5 or 6, it being possible individual hydrogen atoms by F, Cl, NO _2, CF _3, OR ^13, CN or C _1-5 Alkyl may be replaced;
R ⁷ , R ⁸ , R ⁹ and R ^{10 are} independently H, F, Cl, Br, NO ₂ , CF ₃ , OH, OCH ₃ , CN, COOR ¹³ , NR ¹⁴ R ¹⁵ ; C _1-5 alkyl, heteroaryl, unsubstituted or substituted singly or multiply with benzyl, CH ₃ , Cl, F, OCH ₃ or OH;
wherein R ^{13 is} H or C _1-5 alkyl;
R ¹⁴ and R ^{15 are} independently H or C _1-5 alkyl;
X is O, S, SO, SO ₂ or NR ¹⁷ ;
R ¹⁷ is H; C _1-5 alkyl, saturated or unsaturated, branched or unbranched; COR ¹² or SO ₂ R ¹² ;
in the form of their pure diastereomers, their racemates, their pure enantiomers, or in the form of mixtures of the stereoisomers in a bellebigen mixing ratio; as bases or in the form of their salts, in particular the physiologically tolerated salts or salts of physiologically acceptable acids or cations.

The K _i values are determined on recombinant CHO cells expressing the respective receptor.

The term "ORL1 / μ defined as 1 / [K _{(ORL 1)} / K _(μ) ]" is abbreviated to "ORL1 / μ". The term "at least 100 nM" means that the affinity is at 100 nM or better (= lower K _t , for example 99.9 nM).

Surprisingly, it has been found that compounds having a ratio of ORL1 / μ of 0.1 to 30 form a window in which the ORL-1 component causes a significant reduction of some μ-typical side effects such as respiratory depression and dependency, However, the antiopioid effect of this component does not yet prevent the analgesic effect in acute pain. In contrast to acute pain, chronic analgesia even results in analgesic synergism of ORL1 and μ components, that is, the respective contributions that provide the effect of the compounds on the individual receptor for overall efficacy. As a result, in compounds having a ratio of ORL1 to μ defined as 1 / [K _{i (ORL1)} / K _{t (μ)} ] of 0.1 to 30, a significantly increased efficacy is achieved, which allows the dose to be compared to reduce acute pain, to come to a satisfactory effect. Preferably, the ratio of ORL1 to μ is defined as 1 / [K _{t (ORL1)} / K _{t (μ)} ] 0.1 to 20. The compounds according to the invention may also be metabolites of a parent substance, wherein the metabolites individually or as metabolite mixture in combination with the remaining amount of the parent substance may possess the properties of the invention.

For the potency of the compounds, it is important that the affinity of the compounds or the affinity of the metabolites to the μ-opioid receptor is at least 100 nM (K _l value human). This value is in the range of well-effective μ-opioids in clinical use such as hydrocodone (human μ-OR Ki 76 nM), ketobemidone (human μ-OR Ki 22 nM) and meptazinol (Ki 150 nM human μ-OR). Preferably, the affinity of the compounds for μ-opioid receptor is at least 50 nM.

The abovementioned surprising properties of compounds having the properties according to the invention have been confirmed by numerous animal experiments. The compounds have a range of ORL1 / μ portions and occupy the exceptional position of the mixed ORL1 / μ agonists in the range of the invention. For the comparative studies, drugs were selected that are now used for the treatment of severe pain. The reference substances B1-B6 are the μ-opioids fentanyl, sufentanil, morphine, oxycodone, buprenorphine and hydromorphone, all of which are stage 3 opioids according to WHO phased approach to the treatment of pain. These medicines represented the gold standard for severe pain therapy today.

The ORL1 receptor is homologous to the μ, κ and δ opioid receptors and the amino acid sequence of the endogenous ligand, the nociceptin peptide, is very similar to those of the known opioid peptides. The nociceptin-induced activation of the receptor results in inhibition of adenylate cyclase via coupling with G _{i / o} proteins, inhibition of voltage-dependent calcium channels and activation of potassium channels (US Pat. Meunier et al., Nature 377, 1995, pp. 532-535 ; Ronzoni et al., Exp Opin Ther Patents 2001, 11, 525-546 ).

The nociceptin peptide exhibits pronociceptive and hyperalgesic activity in various animal models after intracerebroventic administration ( Reinscheid et al., Science 270, 1995, pp. 792-794 ). These findings can be explained as an inhibition of stress-induced analgesia ( Mogil et al., Neuroscience 75, 1996, pp. 333-337 ).

On the other hand, in various animal models after intrathecal application, an antinociceptive effect of nociceptin was also shown. ( Abdulla and Smith, J. Neurosci., 18, 1998, pp. 9685-9694 ). Nociceptin thus has, depending on the site of action and physiological state of the organism, antinociceptive and pronociceptive properties.

Furthermore, it is known that the endogenous ORL-1 ligand nociceptin has an effect in neuropathic pain. In addition, it has been demonstrated that nociceptin and morphine have a synergistic effect in neuropathic pain ( Courteix et al., Pain 2004, 110, 236-245 ). However, nociceptin alone is not effective after systemic administration in acute pain (measured in the tail-flick test). Therefore, pure ORL1 agonists may be suitable for the treatment of neuropathic pain. Does the pain to be treated occur in a mixed form or is it typical of neuropathic pain? Spontaneous pain on, however, pure ORL-1 agonists are not sufficiently effective according to findings from animal experiments.

From the literature, mixed ORL1 / μ agonists are already known, for example from EP 0997464 or WO 1999059997 , However, these documents disclose only structures that are described as mixed ORL1 / μ agonists without providing specific biological data, but do not disclose that compounds in the affinity region of the invention have advantages. WO 2001039775 discloses mixed ORL1 / μ agonists as well as a general, unspecified range in which compounds may possess ORL1 and μ affinity, but without evidence of an advantage of such compounds.

Enhanced effect on chronic pain versus pure μ-opioids a) Neuropathic pain

In contrast to classical μ agonists, surprisingly, in mixed ORL1 / μ agonists in the range of 0.1 to 30, preferably to 20, a significant increase in analgesic efficacy in neuropathic pain models can be observed. In antagonization experiments it has been shown that the ORL1 component in mixed ORL1 / μ agonists directly contributes to the analgesic effect ( Fig. 3 ). The direct comparison of a substance with an ORL1 / μ ratio of 0.5 (Compound A4) and morphine in naïve and neuropathic animals shows that after neuropathy develops, the efficacy of morphine decreases (which corresponds to the clinical situation), whereas for mixed agonists tend to increase ( Fig. 5 . 5a . 6 . 6a ).

In comparison of the analgesic efficacy in the acute pain model (tail-flick, rat / mouse) and in the neuropathic pain models Chung model in the rat and the Bennett model on rat / mouse, the exceptional position of the compounds with the properties according to the invention is evident (see FIGS and 2). In contrast to pure μ opioids, where the analgesic potency in the neuropathic pain model is lower than in the acute pain model (up to factor 5), the analgesic potency of mixed ORL1 / μ agonists is a factor of 2 to 10 higher in the neuropathic model than in the acute pain model , For example, the clinically used μ-opioid is oxycodone in neuropathy pain three to five times less potent compared to acute pain (depending on the animal model); on the other hand, a mixed agonist with an ORL1 / μ ratio of 0.5 (compound A4) is about ten times more potent in neuropathic pain than in acute pain.

The upper limit of the range in which the effect occurs, is occupied by the compounds B8, which has an ORL1 / μ ratio of 0.03 and in the neuropathic model is no longer better than in the acute pain model. In contrast, Example A1 (ORL1 / μ ratio 0.1) is even more effective by a factor of 10.

Compound A11, with an ORL1 / μ ratio of 20, has intrathecally given an even higher potency enhancement in neuropathic pain. The compound is still very effective in acute pain after systemic administration (tail-flick mouse iv ED ₅₀ = 0.42 mg / kg). Compound B9 with an ORL1 / μ ratio of 140: 1, given intrathecally, also has a high potency enhancement in nepathyroid pain. However, the compound is no longer effective after systemic administration in acute pain due to the low μ-component. The endogenous ORL-1 ligand nociceptin no longer has an effect in the acute-pain model (tail-flick iv). Because of the antiopioid properties of the ORL1 component, in compounds that have an ORL1 component that is significantly better than 30: 1 compared to the μ component, the effect in acute pain is too poor to increase in potency with a stage 3 antibody. Opioid to be comparable. This relationship can be illustrated by antagonizing the ORL1 component. The findings show that the compounds having the properties of the invention form a defined subset of mixed μ / ORL1 agonists possessing the disclosed extraordinary properties. The lower limit of the range according to the invention is therefore 30, preferably 20.

In antagonizing experiments in the Chung model, it has been demonstrated that the analgesic efficacy of the mixed ORL1 / μ agonists is based on both components. After administration of mixed ORL1 / μ agonists, a partial abrogation of the analgesic effect can be demonstrated with a μ antagonist as well as with an ORL1 antagonist (Figures 3 and 4). This confirms that both the μ-opioid component and the ORL1 component contribute to the effect in chronic neuropathic pain.

The antagonization experiments clearly show that the properties according to the invention are directly attributable to the ORL1-agonistic and the μ-agonistic action of the compounds.

In order to exclude a possible influence of pain quality (tail-flick, nociceptive stimulus vs. chung, tactile allodynia) in comparing the different efficacy in acute pain and neuropathy pain, A4 and morphine were compared in Chung and sham-operated animals The direct comparison shows that although morphine has a very good effect on the sham-operated animal, which corresponds to the situation in acute pain - but that after the formation of neuropathy in the operated animal, the effectiveness of morphine is comparatively much lower ( Figure 7 ). This corresponds to the clinical situation and reflects one of the problems of μ-opioids in the clinic, A4 on the other hand shows a clear effect on the sham-operated animal, which even increases after the formation of neuropathy ( Figure 8 ). This shows the distinct advantage of mixed ORL1 / μ agonists as compared to pure μ-opioids in the treatment of neuropathic pain.

The compounds according to the invention with an ORL1 / μ ratio defined as 1 / [K _(ORL1) / K _(μ) ] of 0.1 to 30, preferably of 0.1 to 20, with a K _i value on the μ-opioid Receptor of less than 100 nM can therefore be used to treat neuropathic pain.

Separation of antinociceptive and antilailodynic effect in neuropathic animals

Another advantage of the mixed ORL1 / μ agonists in the range according to the invention by the separation of antinociceptive and antiallodynic effect. In so-called allodynia, pain is certainly evoked by a non-painful stimulus (eg, touch, warm, cold-crust) in an unaffected body region. Mechanical allodynia is typical in post-zosteric neuralgia, while the ballad nodule is common in posttraumatic Nerve lesions and some polyneuropathies. Especially in diabetic neuropathy, the occurrence of mechanical allodynia is typical ( Calcutt and Chaplan, Br. J. Pharmacol. 1997, 122, 1478-1482 ).

In certain patient groups of chronic pain patients, it is advantageous to combat allodynia and hyperalgesia, but the normal pain sensation remains largely intact. These patients, for whom the protective mechanism of pain makes sense in everyday life, therefore need a medication that specifically fights only allodynia and hyperalgesia, but leaves the general sensation of pain as unaffected as possible. This applies, for example, to postzosteric neuralgia, in which pain is typically triggered by stimuli usually not painful at all, such as by light touch or clothing.

In the Chung model, it is possible to distinguish between antinociceptive (contralateral) and antiallodynic (ipsilateral) effects by comparative testing of the pain response to the ipsilateral and contralateral paw (relative to the side on which the spinal nerve ligature was placed).

For the μ-agonist morphine, a purely antiallodynic effect could only be achieved after administration of 1 mg / kg iv. to be watched. The maximum effectiveness is 29% MPE (maximum possible effect), which corresponds to a recognizable, but weak effect. At the next higher dose (2.15 mg / kg iv), there is already a marked antinociceptive effect (Figures 5, 5a). Thus, a clear distinction between clear antiallodynic effect and antinociceptive effect in morphine is not achievable here.

In contrast, the maximum, purely antiallodynic effect of A4 is 56% MPE. This is iv at a test dose of 1 μg / kg. achieved and corresponds to a good effectiveness (Figures 6, 6a). This shows a further advantage of the mixed ORL1 / μ agonists compared to pure μ-opioids.

It is therefore also preferable that the compounds having an ORL 1 / μ ratio of 0.1 to 30, preferably 1:10 to 20: 1, at a K _i value at the μ-opioid receptor of below 100 nM for the treatment of allodynia, hyperalgesia and spontaneous pain, preferably at a dosage in which the general sensation of pain is largely maintained. The preservation of the general sensation of pain in humans can be checked in the cold pressor model ( Enggaard et al., Pain 2001, 92, 277-282 ).

It is therefore preferred to include the compounds having an ORL1 / μ ratio of 0.1 to 30, preferably 0.1 to 20, with a K _i value at the μ-opioid receptor of less than 100 nM for the treatment of pain postzosteric neuralgia.

For a more detailed study of the diverse forms of neuropathy pain, A4 was investigated in a model for the investigation of cytostatic-induced polyneuropathy pain. The cytostatic-induced polyneuropathy pain forms a clinically very relevant subset of neuropathic pain. Polyneuropathy was induced by administration of the cytostatic drug vincristine. Thus, a clinical picture of the clinical situation after chemotherapy with vincristine developed on the rat. As comparison substance morphine was examined here.

A4 showed a significant efficacy from a dose of 1 μg / kg, ie, from a dose that is in the range of ED ₅₀ in chronic pain at the lower dose of 0.464 μg / kg, but no significant efficacy was seen ( Fig. 24 ). For morphine a good efficacy is observed from a dosage of 2.15 mg / kg (ED ₅₀ Chung rat 3.7 mg / kg).

• 1.) überraschenderweise die Wirksamkeit von A4 noch einmal besser ist als in anderen Neuropathieschmerzformen und
• 2.) die anti-hyperalgetische Wirkung von A4 bereits in einem Dosisbereich vorhanden ist, in dem noch keine anti-nociceptive Wirkung auftaucht (Abbildung 26) und damit die Linderung des Polyneuropathieschmerzes möglich ist, ohne das Akutschmerzempfinden zu beeinträchtigen.

Furthermore, the efficacy against diabetic induced polyneuropathy pain was investigated. This form of pain was investigated in a rat model with the administration of streptozotocin inducing diabetic polyneuropathy. A4 showed a significant inhibition of diabetic induced mechanical hyperalgesia in the rat even at the lowest dose tested of 0.316 μg / kg iv, and thus in a lower dose range than in cytostatic-induced polyneuropathy pain, where no significant dose was observed at a dose of 0.464 μg / kg Effectiveness was observed. In this low dose range, A4 had no effect on the control group. This means that in diabetic induced polyneuropathy pain

• 1.) Surprisingly, the effectiveness of A4 is even better than in other types of neuropathy and
• 2.) the anti-hyperalgesic effect of A4 is already present in a dose range in which there is no anti-nociceptive effect ( Figure 26 ) and thus the relief of polyneuropathy pain is possible without affecting the acute pain sensation.

In the case of morphine, on the other hand, an anti-hyperalgesic effect can only be observed in a dose range in which an antinociceptive effect also appears in the control group ( Figure 27 ). Since in the diabetic induced polyneuropathy pain the standard therapy today is not the administration of a μ agonist such as morphine but, inter alia, the administration of pregabalin, pregabalin was investigated as a further comparison in the same model. Again, it was found that an anti-hyperalgesic effect is observed only in a dose range in which an antinociceptive effect also appears in the control group ( Figure 28 ). This underlines the extraordinary effectiveness of the compounds having the properties according to the invention in diabetic induced polyneuropathy pain.

Therefore, compounds having an ORL1 / μ ratio of from 0.1 to 30, preferably from 0.1 to 20, with a K _i value at the μ-opioid receptor of less than 100 nM are particularly preferably used for the treatment of diabetic polyneuropathy pain.

b) inflammatory pain

In two in vivo models (single-motor-unit derivation in spinal cord rats and CFA ** -induced hyperalgesia) it was shown that after chronic inflammation the efficacy of mixed ORL1 / μ agonists is increased.

Single-engine-unit discharges in spinalized rats. Comparison of naive animals and animals after carrageenan-induced inflammation.

In the rat, it is observed that 24 h after induction of inflammation, the antinociceptive effect of A4 (ratio ORL1 / μ 1: 2, Figures 9 and 10) and A11 (ratio ORL1: μ 20: 1) compared to the value before the inflammation is significantly increased. The antinociceptive effect of the μ-agonist morphine tends to be weaker after inflammation. (Figures 11 and 11a). This shows that after chronic inflammation the efficacy of mixed ORL1 / μ agonists is increased, whereas the pure μ agonists are not

CFA-induced hyperalgesia

In a chronic inflammatory pain model, inflammation of the hind paw was induced by injection of CFA. 1h, 3h, 24h and 4 days after inflammatory induction, tactile hyperalgesia and nociception were determined. While morphine showed a slightly decreasing antihyperalgesic or a constant antinociceptive effect over the entire investigation period, antihyperalgesic and antinociceptive effects of A4 increased over 24 h. The effect is stable for at least 4 days (Figures 12 and 12a). This shows that, analogously to the situation with neuropathic pain, mixed ORL1 / μ agonists in inflammatory pain are characterized by a marked increase in activity compared to analgesia in acute pain.

Visceral inflammatory pain

Comparative Testing of A4 and Fentanyl In a model of transmitted allodynia and hyperalgesia in mice after mustard oil-induced non-neurogenic visceral inflammation, the severity of the mixed ORL1 / μ agonist was significantly greater for both pain parameters compared to the pure μ-opioid. The analgesic efficacy of A4 with respect to both tested pain parameters is about a factor of 6 to 7 higher than in acute pain. In contrast, the analgesic efficacy of fentanyl in visceral inflammatory pain is less than in acute pain. This also shows that, analogously to the situation with neuropathic pain, mixed ORL1 / μ agonists are distinguished by a marked increase in the effect of analgesia on visceral inflammatory pain compared to acute pain. The compounds thus show, in addition to the reduced side effects compared to pure μ-opioids, a better efficacy in inflammatory pain.

Mixed ORL1 / μ agonists with an ORL1: μ ratio of 0.1 to 30, preferably from 0.1 to 20, with a K _r value at the μ-opioid receptor of less than 100 nM, are characterized by a high Efficacy in inflammatory pain. The invention therefore also relates to the use of compounds having an ORL1: μ ratio of from 0.1 to 30, preferably from 0.1 to 20, with a K _r value at the μ-opioid receptor of less than 100 nM for the treatment of Patients suffering from inflammatory pain. The inflammatory pain can be triggered, for example, by rheumatoid arthritis or pancreatitis.

It has been shown that mixed ORL1 / μ agonists with an ORL1: μ ratio of 0.1 to 30, preferably from 0.1 to 20, with a K _i value at the μ-opioid receptor of less than 100 nM im chronic pain shows an increase in activity compared to acute pain. It is therefore preferred to use the compounds in chronic pain in a dosage that is below the dosage needed in acute pain. Preferably, the compounds are applied in chronic pain in a dosage that is at least a factor of 2 lower than the dosage used in acute pain, more preferably at least a factor of 5 lower. In animals, the dosage can be determined as ED ₅₀ in the tail-flick, on humans in the cold pressor model ( Enggaard et al., Pain 2001, 92, 277-282 ).

c) acute pain

The mixed ORL1 / μ agonists with an ORL1: μ ratio of 0.1 to 30, preferably 0.1 to 20, show full activity in various acute-pain models and species after intravenous administration. Both rat and mouse (tail-flick, Figure 13 ) this effect could be shown.

In comparison of mixed ORL1 / μ agonists with pure μ agonists, the mixed ORL1 / μ agonists show comparable efficacy with better tolerability. These results show that the mixed ORL1 / μ agonists are also excellent in acute pain. The compounds are comparable in efficacy in acute pain with the level-3 opioids. This means that there are compounds that have their analgesic effect perform a different mechanism than the pure μ antagonists, which have mastered the segment of severe pain management for centuries but have the same potency. In addition to their surprising effect enhancement in chronic pain compared to acute pain, compounds with the binding profile according to the invention also show a significantly improved side-effect profile in comparison to the pure agonists.

d) side effects Opioid-Induced Hyperalgesia

The chronic administration of opioids leads to hyperalgesia in patients with pain (cf. Chu et al. 2006, J. Pain 7: 43-48 ). A similar phenomenon also occurs after acute administration in the withdrawal situation ( Angst et al. 2003, Pain 106: 49-57 ). In the animal model, pure μ-oploids induce transient hyperalgesia after acute administration, which can be detected in the soft-tall-flick model as a transient, pronociceptive phase.
This opioid-induced hyperalgesia can be demonstrated by using a modified tail-flick model with reduced stimulus intensity (25% focal beam intensity) for pure μ-oploids (fentanyl and morphine). In contrast, no transient hyperalgesia was observed following acute administration of mixed ORL1 / μ agonists (A4 and A7) (Figures 14-14c).

This shows that chronic administration of a mixed ORL1 / μ agonist does not induce hyperalgesia or reduced hyperalgesia compared to pure μ-opioids. One of the typical μ-opioid side effects is therefore reduced in mixed ORL1 / μ agonists.

Preference is therefore given to the compounds having an ORL1 / μ ratio of 0.1 to 30, preferably of 0.1 to 20, with a K _i value at the μ-opioid receptor of less than 100 nM for the reduction of opioid-induced hyperalgesia used in the treatment of pain.

Particularly advantageous is the use of the compounds with an ORL1 / μ ratio of 0.1 to 30, preferably from 0.1 to 20, with a K _i value at the μ-opioid receptor of less than 100 nM in the treatment of patients who are at an increased risk of developing hyperalgesia. These include, for example, patients, who already suffer from hyperalgesia and undergo surgery such as irritable bowel syndrome (visceral hyperalgesia), tumor pain patients and patients with musculoskeletal pain, or patients who received intrathecally a potent active opioid such as fentanyl intraoperatively (eg, calf cut patients). The invention therefore also relates to the use of compounds having an ORL1 / μ ratio of from 0.1 to 30, preferably from 0.1 to 20, with a K _r value at the μ-opioid receptor of less than 100 nM for pain relief in patients at increased risk of developing hyperalgesia.

withdrawal

In naloxone-induced mouse withdrawal, it was shown that compounds with an ORL-1 component that is less than a factor of 10 weaker than the μ component suppress withdrawal withdrawal. In contrast, compounds with a weaker ORL1 component trigger withdrawal bounce. In the "withdrawal skipping" test, mice are repeatedly treated with the test substance over a defined period of time. In the case of a μ-opioid, a physical dependence is achieved within this period. At the end of treatment, administration of naloxone, a μ-antagonist, abolishes the effect of the opioid at once. In the case of a physical dependence, the mice show characteristic withdrawal symptoms, which manifest themselves in the form of jumping movements ( Saelens JK, Arch Int Pharmacodyn 190: 213-218, 1971 ).

Due to the ORL1-active component, the compounds having the properties according to the invention have additional properties which are not possessed by the pure μ-opioids and lead to improved therapy. In mouse withdrawal, it was shown that in animals treated with combined ORL1 / μ agonists such as A9, A6 Naloxone causes no or only minimal withdrawal (see Figures 15c-e). A1, on the other hand, shows clear withdrawal symptoms in withdrawal ( Figure 15b ). In spontaneous withdrawal from the rat, whereby the weight of the rat is documented after discontinuation of the test substance over several days, however, a clear difference between morphine and A1 (ORL1: μ 0.1) can be recognized ( Figure 16 ). While the weight of rats decreases by almost 10% after stopping morphine, it only decreases by 3% after discontinuing A9. The ratio ORL1 / μ of 0.1 is also a limit up to which the advantageous effect of the compounds having the properties according to the invention can be observed. These properties make the compounds having an ORL1 / μ ratio of 0.1 to 30, preferably from 0.1 to 20, with a K _i value at the μ-opioid receptor of less than 100 nM, particularly suitable for groups of patients who have an increased risk of dependency on the body. For example, this group may include patients who already have μ opioid experience.

However, in order to suppress the physical dependency, it is preferable that the ORL1 component is slightly increased, but the physical dependency is already reduced at an ORL1: μ ratio of 0.1. Preferably, the ratio ORL1 / μ of a compound for the treatment of pain with simultaneous suppression of withdrawal symptoms is at least 0.25, more preferably at least 0.5. Compounds with this increased ORL1 component are preferably used in patient groups that are at particular risk for physical dependence.

Compounds which have an affinity of at least 100 nM for the μ-opioid receptor and for the ORL1 receptor and which due to the ORL1 component induce a lower withdrawal symptom in the same affinity range than for a μ-opioid, are suitable for the treatment of pain. The effect can be demonstrated by the withdrawal skipping and spontaneous withdrawal models described in the examples.

Reduction of mental dependence / addiction

Mixed ORL1 / μ agonists induce place-conditioning in rats, similar to pure agonists. While the threshold dose for inducing a preference for pure N-opioids (using the example of B1, B3-B6) is well below the analgesic half-maximal effective dose, it is mixed with ORL11 / μ agonists (using the example of A4, A7 and A6). In the range or above the analgesic half-maximal effective dose ( Figure 21 ). This means that mixed ORL1 / μ agonists have a reduced addictive potential compared to pure μ-oploids.

Despite the physical and mental dependence potential of μ-opioids, they have been successfully used in the clinic for a long time, with most patients discontinuing the drug after therapy. However, certain groups of patients are susceptible to addictive behavior. It is therefore preferred to use the compounds having the properties according to the invention for pain therapy in patients with an increased addictive potential.

These groups of patients include, for example, people with mental illnesses, in particular depressive people or people suffering from anxiety disorders ( Paton et al., Journal of Genetic Psychology 1977, 131, 267-289 ). Preferably, therefore, the compounds having the inventive properties are used in patients having a mental illness to reduce the risk of mental dependence during the course of pain therapy. More preferably, the compounds having the pain therapy properties of the present invention are used in patients suffering from depression or anxiety disorders.

Compounds which have an affinity of at least 100 nM for the μ-opioid receptor and for the ORL1 receptor and due to the ORL1 component cause less psychological dependence in comparison to a μ-opioid in the same affinity region can be used for the treatment of pain , This effect can be demonstrated, for example, by antagonization experiments, but also by site preference studies as described in the examples.

respiratory depression

The μ-mediated respiratory depression is significantly reduced in the mixed ORL1 / μ agonists The acute respiratory depressant effect was measured as an increase in the pCO _{2 of} the arterial blood in the rat in an analgesic fully effective dosage as well as in an analgesic Schwellendoslerung.

For pure μ-Opioploden shown on B1 (fentanyl, Figure 17 ) and B4 (oxycodone, Figure 17a ) there is a significant increase in the arterial pCO ₂ at the time of the analgesic maximum due to μ-induced respiratory depression. At a 90-100% effective dose, the pCO ₂ value increases by more than 50%.

In contrast, the pCO ₂ value increases only slightly in mixed ORL1 / μ agonists such as A4, A5, A6, and A9 (Figures 17b-e), even at a very high dose, which is maximally effective analcally for several hours, the arterial pCO ₂ only increases by about 20-30%.

• (1) die Atemdepression nach Antagonisierung der ORL1-Komponente am Beispiel von A4 mit B11 deutlich verstärkt ist (ca 70%), und
• (2) die Atemdepression durch anschließende µ-Antagonisierung mit Naloxon komplett unterdrückt wird (Abbildung 18).

Antagonization experiments have shown that

• (1) the respiratory depression after antagonization of the ORL1 component is markedly increased in the case of A4 with B11 (approx. 70%), and
• (2) respiratory depression is completely suppressed by subsequent μ antagonization with naloxone ( Figure 18 ).

This shows that the reduced respiratory depression in mixed ORL1 / μ agonists with the properties according to the invention is attributable to the ORL1 component. Respiratory depression is completely triggered by the μ component. The antagonization experiments prove that the reduction of respiratory depression by the ORL1 component causes it to become wild.

Since the respiratory depression triggered by μ-oploids can lead to serious complications, especially during anesthesia, the compounds with the properties according to the invention can be used for anesthesia or anesthesia. It is preferred if the half-life of the compound is less than one hour, more preferably less than 30 minutes.

In this case, the half-life is understood to mean the time in which half of the absorbed compound undergoes a change in the state of the invention and / or is excreted.

Even after surgery, the risk of respiratory depression is increased. By using the compounds with an ORL1 / μ ratio of 0.1 to 30, preferably from 0.1 to 20, with a K _r value at the μ-opioid receptor of less than 100 nM higher doses can be used postoperatively and thereby, if greater analgesia is required than with pure μ agonists. It is therefore preferred to use the compounds having the properties according to the invention for the treatment of postoperative pain.

Since the risk of respiratory depression is significantly increased in people over the age of 60 compared to younger people, as has been shown by studies ( Cepeda et al., Clinical Pharmacology & Therapeutics 2003, 74, 102-112 ), the compounds having an ORL1 / μ ratio of from 0.1 to 30, preferably from 0.1 to 20, with a K _i value at the μ-opioid receptor of less than 100 nM, are preferred for the treatment of pain in patients used for over 60 years. Therefore, it is particularly preferred to use the compounds having the properties according to the invention for anesthesia, anesthesia-accompanying or postoperatively in patients over 60 years. More preferably, the compounds are also used on patients over 60 years of age for the treatment of neuropathic pain.

The reduction of respiratory depression by the ORL1 component can be demonstrated by antagonizing experiments as shown in the examples. The invention therefore also relates to the use of compounds which have an affinity of at least 100 nM for the p-opioid receptor and for the ORL1 receptor and, due to the ORL1 component, have a lower respiratorypresion in comparison with a μ-opioid in the same affinity region , for anesthesia-accompanying or postoperative treatment of pain.

Higher scores in mixed ORL1 / μ agonists Due to the reduced μ-OR-mediated respiratory depression on the one hand and the increased efficacy in neuropathic pain on the other hand, the mixed ORL1 / μ agonists are characterized by significantly increased safety margins compared to pure μ-opioids. The threshold dose (ED ₁₀ ) for an increase in the arterial pCO ₂ is for mixed ORL1 / μ agonists with the properties according to the invention shown in Examples A1, A5, A7, A6 and A4 by about a factor of 3 to 20 above that in the neuropathic Pain Semi-maximal Effective Dose (ED ₅₀ ) ( Figure 20 ). This means that, especially in the case of chronic pain conditions, the distance to the possible opioid side effects due to the increased effectiveness of the compounds having the properties according to the invention on the one hand and the anti-ooploid component on the other hand is so great that the typical μ side effects are comparatively reduced while maintaining the same efficacy in the therapeutic area occur.

Due to the higher distance between effect and side effect in the compounds having the properties according to the invention, the compounds are particularly suitable for the treatment of pain in Pelliativpatienten. Due to their multi-morbid condition, palliative patients are particularly affected by opioid-type side effects. The invention therefore also relates to the use of compounds having an ORL1 / μ ratio of from 0.1 to 30, preferably from 0.1 to 20, with a K _i value at the μ-opioid receptor of less than 100 nM in the case of Pain treatment of palliative patients.

• Wirkverstärkung im chronischen Schmerz, insbesondere Im neuropathischen Schmerz und im Entzündungsschmerz
• Deutlich reduzierte Nebenwirkungen gezeigt am Beispiel der Atemdepression, Entzug/Sucht und opioid-induzierter Hyperalgesie bei vergleichbarer Wirksamkeit im Akutschmerz

Compounds having an affinity for μ-opioid receptor of at least 100 nM (Ki value human) and an affinity for the ORL-1 receptor, wherein the ratio between the affinities ORL1: μ (Ki values) between 0.1 and 30, preferably from 1:10 to 20: 1, therefore, in summary, have in particular the following advantages over the standard therapy with μ-opioids:

• Effect enhancement in chronic pain, especially in neuropathic pain and inflammatory pain
• Significantly reduced side effects demonstrated by the example of respiratory depression, withdrawal / addiction and opioid-induced hyperalgesia with comparable efficacy in acute pain

The compounds which have an affinity for the μ-opioid receptor of at least 100 nM (K _i value human) and an affinity for the ORL-1 receptor, wherein the relationship between the affinities ORL1: μ (K _i values) between 0.1 and 30, preferably from 0.1 to 20, have the aforementioned properties. The observed benefits are not due to properties specific to the compounds tested, but to effects resulting from the mechanism of action. This could be proven by antagonization experiments. It has been shown that the ORL1 component contributes to analgesia, but suppresses the μ-typical side effects. In the field of analgesia, the ORL1 component behaves synergistically, but in the range of the side effects studied opposite. Crucial for this is the ratio of the two components.

The values defining the range of the invention refer to in vitro data; in cases where one or more active metabolites are formed in vivo, the metabolites may affect activity. When metabolites are formed, the following cases can be distinguished:

a) Use of prodrugs

Compounds which do not have the binding profile according to the invention can form metabolites. which have an affinity to the μ-opioid receptor of at least 100 nM (Ki value human) and an affinity for the ORL-1 receptor, the ratio between the affinities ORL1 / μ defined as 1 / [K _(ORL1 ) / K _(μ) ] is between 0.1 and 30, preferably from 0.1 to 20, and therefore nevertheless have the properties according to the invention. This can be determined by determining the K _i values of the metabolites. Therefore, it is also possible to use compounds which form metabolites which have an affinity for the μ-opioid receptor of at least 100 nM (K _i value human) and an affinity for the ORL-1 receptor, the ratio between the affinities ORL1 / μ defined as 1 / [K _{i (ORL 1)} / K _{i (μ)} ] is between 0.1 and 30, preferably from 0.1 to 20, wherein the contribution to the efficacy and / or the reduction of μ-typical side effects by antagonizing experiments is detectable.

b) formation of metabolites which together or together with the parent substance form the profile according to the invention

For example, when a selective μ agonist is partially metabolized to a selective ORL1 agonist and the resulting mixture has the inventive properties, ie, the ratio of ORL1 / μ is defined as 1 / [K _{i (ORL1)} / K _{i (μ)} ] is between 0.1 and 30 and the Ki value at the human μ-opioid receptor is at least 100 nM, the mixture can also be used. These mixtures can also be formed from compounds which have no selectivity but are nevertheless outside the range according to the invention. On the one hand, the properties according to the invention can be demonstrated by determining the binding constants of the mixture which is formed in vivo, it being possible to determine the concentrations by HPLC-MS studies and, secondly, by the contribution of the ORL1 component to the activity amplification in the chronic pain and / or to reduce μ-typical side effects by antagonizing experiments with an ORL1 antagonist. Furthermore, the compounds have the property of being effective in acute pain. Substance mixtures formed by metabolism which have the properties according to the invention, the binding constants of the mixture corresponding to the range according to the invention and the contribution to the activity and / or the reduction of the μ-typical side effects being detectable by antagonization experiments can also be used.

The effects exerted by the compounds of the present invention can also be achieved by administering two or more different substances. This can be demonstrated, on the one hand, by determining the binding constants of the mixture and, on the other hand, by demonstrating the contribution of the ORL1 component to potentiating the effects in chronic pain and / or reducing the μ-typical side effects by antagonizing experiments with an ORL1 antagonist , Furthermore, the compounds have the property of being effective in acute pain.

In addition to at least one compound having the properties according to the invention, the medicaments according to the invention optionally contain suitable additives and / or adjuvants, as well as carrier materials, fillers, solvents, diluents, dyes and / or binders and can be used as liquid dosage forms in the form of injection solutions, drops or juices , as semi-solid dosage forms in the form of granules, tablets, pellets, patches, capsules, patches or aerosols. The choice of excipients etc. as well as the amounts to be used depend on whether the drug is administered orally, perorally, parenterally, intravenously, intraperitoneally, intradermally, intramuscularly, intranasally, buccally, rectally or locally, for example on the skin, mucous membranes or in the mouth the eyes, to be applied. For oral administration, preparations in the form of tablets, dragees, capsules, granules, drops, juices and syrups are suitable, for parenteral, topical and inhalative administration solutions, suspensions, readily reconstitutable dry preparations and sprays. Compounds of the invention in a depot, in dissolved form or in a plaster, optionally with the addition of skin penetration promoting agents, are suitable percutaneous administration preparations. Oral or percutaneous applicable Forms of preparation, the compounds having the properties of the invention or a combination of the invention release delayed. In principle, other active compounds known to the person skilled in the art may be added to the medicaments according to the invention.

The amount of drug to be administered to the patient varies depending on the weight of the patient, the mode of administration, the indication and the severity of the disease. Usually, 0.005 to 20 mg / kg, preferably 0.05 to 5 mg / kg of at least one compound or combination with the properties of the invention are administered.

The compounds A1 to A10, which all have the properties according to the invention, fall under the group of the spirocyclic cyclohexane derivatives. These compounds have an affinity for the μ-opioid receptor and / or the ORL-1 receptor, but a subset of these compounds has the properties according to the invention.

, worin
R¹ und R² unabhängig voneinander für H oder CH₃ stehen, wobei R¹ und R² nicht gleichzeitig H bedeuten;
R³ für Phenyl, Benzyl oder Heteroaryl jeweils unsubstituiert oder einfach oder mehrfach mit F, Cl, OH, CN oder OCH₉ substituiert, steht;
W für NR⁴, O oder S steht und
R⁴ für H; C_1-5-Alkyl, Phenyl; Ober eine C_1-3-Alkyl-Gruppe gebundenes Phenyl, COR¹²; SO₂R¹² steht,
wobei R¹² H; C_1-7-Alkyl, verzweigt oder unverzweigt, gesättigt oder ungesättigt, unsubstituiert oder einfach oder mehrfach mit OH, F oder COOC_1-4-Alkyl substituiert; C_4-6-Cycloalkyl; Aryl-, oder Heteroaryl, unsubstituiert oder einfach oder mehrfach mit F, Cl, Br, CF₃, OCH₃, C_1-4-Alkyl, verzweigt oder unverzweigt, unsubstituiert oder substituiert mit F, Cl, CN, CF₃, OCH₃ oder OH; oder über gesättigtes oder ungesättigtes C_1-3-Alkyl gebundenes Phenyl oder Heteroaryl, unsubstituiert oder einfach oder mehrfach mit F, Cl, Br, CF₃, OCH₃, C_1-4-Alkyl, verzweigt oder unverzweigt, unsubstituiert oder substituiert mit F, Cl, CN, CF₃, OCH₃ oder OH substituiert; oder Ober gesättigtes oder ungesättigtes C_1-3-Alkyl gebundenes C_5-6-Cycloalkyl; OR¹³; NR¹⁴R¹⁵ bedeutet;
R⁵ für H; COOR¹³, CONR¹³, OR¹³; C_1-5-Alkyl, gesättigt oder ungesättigt, verzweigt oder unverzweigt, unsubstituiert oder einfach oder mehrfach mit OH, F, CF₃ oder CN substituiert, steht;
R⁶ für H steht;
oder R⁵ und R⁶ gemeinsam (CH₂)_n mit n = 2, 3, 4, 5 oder 6 bedeuten, wobei einzelne Wasserstoffatome auch durch F, Cl, NO₂, CF₃, OR¹³, CN oder C_1-5-Alkyl ersetzt sein können;
R⁷, R⁸, R⁹ und R¹⁰ unabhängig voneinander für H, F, Cl, Br, NO_2- CF₃, OH, OCH3, CN, COOR¹³, NR¹⁴R¹⁵; C_1-5-Alkyl, Heteroaryl, unsubstituiert oder einfach oder mehrfach mit Benzyl, CH₃, Cl, F, OCH₃ oder OH substituiert, stehen;
wobei R¹³ H oder C_1-5-Alkyl bedeutet;
R¹⁴ und R¹⁵ unabhängig voneinander H oder C_1-5-Alkyl bedeuten;
X für O, S, SO, SO₂ oder NR¹⁷ steht;
R¹⁷ für H; C_1-5-Alkyl, gesättigt oder ungesättigt, verzweigt oder unverzweigt; COR¹² oder SO₂R¹² steht,
in Form ihrer reinen Diastereomeren, ihrer Racemate, ihrer reinen Enantiomeren, oder in Form von Mischungen der Stereoisomeren in einem beliebigen Mischungsverhältnis;
als Basen oder in Form ihrer Salze, Insbesondere der physiologisch verträglichen Salze oder Salze physiologisch verträglicher Säuren oder Kationen;
die eine Affinität zum µ-Opioid-Rezeptor von mindestens 100 nM (K_i-Wert human) und eine Affinität zum ORL-1-Rezeptor aufweisen, wobei das Verhältnis zwischen den Affinitäten ORL1/µ definiert als 1/[K_i(ORL1)/K_i(µ)] von 0,1 bis 30 liegt, sind auch zur Herstellung eines Arzneimittels zur Behandlung von diabetischem Polyneuropathieschmerz, postoperativem Schmerz oder Schmerzen bei postzosterischer Neuralgie geeignet.Compounds from the group of spirocyclic cyclohexane derivatives of general formula I.

in which
R ¹ and R ^{2 are} independently H or CH ₃ , wherein R ¹ and R ^{2 are} not H at the same time;
R ^{3 represents} phenyl, benzyl or heteroaryl in each case unsubstituted or monosubstituted or polysubstituted by F, Cl, OH, CN or OCH ₉ ;
W stands for NR ⁴ , O or S. and
R ⁴ for H; C _1-5 alkyl, phenyl; Phenyl bonded to a C _1-3 alkyl group, COR ¹² ; SO ₂ R ¹² is
where R ^{12 is} H; C _1-7 -alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or poly-substituted by OH, F or COOC _1-4 -alkyl; C _4-6 cycloalkyl; Aryl or heteroaryl, unsubstituted or mono- or polysubstituted by F, Cl, Br, CF ₃ , OCH ₃ , C _1-4 alkyl, branched or unbranched, unsubstituted or substituted by F, Cl, CN, CF ₃ , OCH ₃ or OH; or phenyl or heteroaryl bonded via saturated or unsaturated C _1-3 -alkyl, unsubstituted or mono- or polysubstituted by F, Cl, Br, CF ₃ , OCH ₃ , C _1-4 -alkyl, branched or unbranched, unsubstituted or substituted by F Cl, CN, CF ₃ , OCH ₃ or OH substituted; or C _5-6 -cycloalkyl bonded over saturated or unsaturated C _1-3 -alkyl; OR ¹³ ; NR ¹⁴ R ¹⁵ means;
R ⁵ is H; COOR ¹³ , CONR ¹³ , OR ¹³ ; C _1-5 alkyl, saturated or unsaturated, branched or unbranched, unsubstituted or monosubstituted or polysubstituted by OH, F, CF ₃ or CN;
R ^{6 is} H;
or R ⁵ and R ⁶ together are (CH ₂ ) _n with n = 2, 3, 4, 5 or 6, wherein individual hydrogen atoms are also represented by F, Cl, NO ₂ , CF ₃ , OR ¹³ , CN or C _1-5 Alkyl may be replaced;
R ⁷ , R ⁸ , R ⁹ and R ^{10 are} independently H, F, Cl, Br, NO ₂ -CF ₃ , OH, OCH 3, CN, COOR ¹³ , NR ¹⁴ R ¹⁵ ; C _1-5 alkyl, heteroaryl, unsubstituted or substituted singly or multiply with benzyl, CH ₃ , Cl, F, OCH ₃ or OH;
wherein R ^{13 is} H or C _1-5 alkyl;
R ¹⁴ and R ^{15 are} independently H or C _1-5 alkyl;
X is O, S, SO, SO ₂ or NR ¹⁷ ;
R ¹⁷ is H; C _1-5 alkyl, saturated or unsaturated, branched or unbranched; COR ¹² or SO ₂ R ¹² ,
in the form of their pure diastereomers, their racemates, their pure enantiomers, or in the form of mixtures of the stereoisomers in any mixing ratio;
as bases or in the form of their salts, in particular the physiologically tolerated salts or salts of physiologically acceptable acids or cations;
having an affinity for the μ-opioid receptor of at least 100 nM (K _i value human) and an affinity for the ORL-1 receptor, the ratio between the affinities ORL1 / μ being defined as 1 / [K _{i (ORL1)} / K _{i (μ)} ] is from 0.1 to 30, are also useful in the manufacture of a medicament for the treatment of diabetic neuropathy pain, postoperative pain, or pain in postzosteroid neuralgia.

Examples used abbreviations

AUC

Area under the curve

CFA

Complete Freund's adjuvant

DBTC

dibutyltin

MPE

Maximum possible effect

Kommerziell erhältlich B2 (Sufentanil)

Kommerziell erhältlich B3 (Morphin)

Kommerziell erhältlich B4 (Oxycodon)

Kommerziell erhältlich B5 (Buprenorphin)

Kommerziell erhältlich B6 (Hydromorphon)

Kommerziell erhältlich B7 (L-Methadon)

Kommerziell erhältlich B8

Synthese analog zu A1 A1

Beispiel 49, EP1560835 1,1-(3-Methylamino-3-phenylpentamethylen)-6-fluor-1,3,4,9-tetrahydropyrano[3,4-b]indol Hemicitrat A2

Beispiel 28, EP1560835 1,1-(3-Methylamino-3-phenylpentamethylen)-1,3.4,9-tettahydropyrano[3,4-b]indol Hemicitrat A3

Beispiel 8, WO200566183 1,1-[3-Dimethylamino-3-(3-thlenyl)pentamethylen]- 1,3,4,9-tetrahydropyrano[3,4-b]indol Hemicitrat A4

Beispiel 24, EP1560835 1,1-(3-Dimethylamino-3-phenylpentamethylen)-6-fluor-1,3,4,9-tetrahydropyrano[3,4-b]indol Hemicitrat, A5

Beispiel 15, WO200566183 1,1-[3-Methylamino-3-(2-thienyl)pentamethylen]-1,3,4,8-tetrahydro-pyrano[3,4-b]-6-fluorindol Citrat A6

Beispiel 10, WO200566183 1,1-[3-Dimethytamino-3-(2-thienyl)pentamethylen]-1,3,4,9-tetra-hydropyrano[3,4-b]-6-fluorindol Hemicitral A7

Beispiel 7, WO200566183 1,1-[3-Dimethylamino-3-(2-thienyl)pentamethylen]- 1,3,4,9-tetra-hydropyrano[3,4-b]indol Citrat A8

Beispiel 13, WO200566183 1,1-[3-Dimethylamino-3-(3-thienyl)pentamethylen]- 1.3,4,9-tetra-hydropyrano[3,4-b]-6-fluorindol Hemicitrat A9

Beispiel 3, EP1560835 1,1-(3-Dimethylamino-3-phenylpentamethylen)-1,3,4,9-tetrahydropyrano[3,4-b]indol Hemicitrat A10

Beispiel 14, WO200566183 1,1-[3-Methylamino-3-(2-thienyl)pentamethylen]-1,3,4,9-tetrahydro-pyrano[3.4-b]indol Citrat A11

EP 08856514 89

Beispiel 59, EP1392641 + Enantiomerentrennung B10 (Nociceptin) Peptid, endogener Ligand Kommerziell erhältlich B11

ORL1-Antagonist WO 9854168 The invention is illustrated by the following examples. Typical representatives were representative of μ agonists, mixed μ / ORL1 agonists, ORL1 agonists as well as an ORL1 antagonist used. As a μ-antagonist, the clinically used compound naloxone was used. These exemplary compounds have been subjected to a variety of studies, which prove the exceptional position of the compounds having the properties according to the invention. description structure Source or manufacturing process B1 (fentanyl)

Commercially available B2 (Sufentanil)

Commercially available B3 (morphine)

Commercially available B4 (oxycodone)

Commercially available B5 (buprenorphine)

Commercially available B6 (hydromorphone)

Commercially available B7 (L-methadone)

Commercially available B8

Synthesis analogous to A1 A1

Example 49, EP1560835 1,1- (3-methylamino-3-phenylpentamethylene) -6-fluoro-1,3,4,9-tetrahydropyrano [3,4-b] indole hemicitrate A2

Example 28 EP1560835 1,1- (3-Methylamino-3-phenylpentamethylene) -1,3,4,9-tettahydropyrano [3,4-b] indole hemicitrate A3

Example 8 WO200566183 1,1- [3-Dimethylamino-3- (3-thlenyl) pentamethylene] -1,3,4,9-tetrahydropyrano [3,4-b] indole hemicitrate A4

Example 24 EP1560835 1,1- (3-dimethylamino-3-phenylpentamethylene) -6-fluoro-1,3,4,9-tetrahydropyrano [3,4-b] indole hemicitrate, A5

Example 15 WO200566183 1,1- [3-Methylamino-3- (2-thienyl) pentamethylene] -1,3,4,8-tetrahydro-pyrano [3,4-b] -6-fluoroindole citrate A6

Example 10 WO200566183 1,1- [3-Dimethytamino-3- (2-thienyl) pentamethylene] -1,3,4,9-tetrahydropyrano [3,4-b] -6-fluoroindole hemicitral A7

Example 7 WO200566183 1,1- [3-Dimethylamino-3- (2-thienyl) pentamethylene] -1,3,4,9-tetrahydropyrano [3,4-b] indole citrate A8

Example 13 WO200566183 1,1- [3-Dimethylamino-3- (3-thienyl) pentamethylene] -1,3,4,9-tetrahydropyrano [3,4-b] -6-fluoroindole hemicitrate A9

Example 3, EP1560835 1,1- (3-dimethylamino-3-phenylpentamethylene) -1,3,4,9-tetrahydropyrano [3,4-b] indole hemicitrate A10

Example 14, WO200566183 1,1- [3-Methylamino-3- (2-thienyl) pentamethylene] -1,3,4,9-tetrahydro-pyrano [3,4-b] indole citrate A11

EP 08856514 89

Example 59, EP1392641 + Enantiomeric separation B10 (nociceptin) Peptide, endogenous ligand Commercially available B11

ORL1 antagonist WO 9854168

Measurement of ORL1 binding

The cyclohexane derivatives of the general formula were investigated in a receptor binding assay with ³ H-nociceptin / orphanin FQ with membranes from recombinant CHO-ORL1 cells. This test system was tested according to the Ardati et al. (Mol. Pharmacol., 51, 1997, pp. 816-824 ) method. The concentration of ³ H. nociceptin / orphanin FQ in these experiments was 0.5 nM. The binding assays were carried out with in each case 20 μg membrane protein per 200 μl batch in 50 mM Hepes, pH 7.4, 10 mM MgCl ₂ and 1 mM EDTA. The binding to the ORL1 receptor was determined using 1 mg WGA-SPA beads ( Amersham Pharmacia, Freiburg), by incubation of the batch at RT for one hour and subsequent measurement in the scintillation counter Trilux (Wallac, Finland). The affinity is given in Table 1 as nanomolar K _i value in% inhibition at c = 1 μM.

Measurement of μ binding

The receptor affinity for the human μ-opiate receptor was determined in a homogeneous batch in microtiter plates. For this purpose, serial dilutions of the respective substances to be tested with a receptor membrane preparation (15-40 μg of protein per 250 μl incubation mixture) of CHO-K1 cells expressing the human μ-opiate receptor (RB-HOM receptor membrane preparation from NEN, Zaventem, Belgium) in the presence of 1 nmol / l of the radioactive ligand [ ³ H] - Naloxone (NET719, NEN, Zaventem, Belgium) and 1 mg WGA-SPA beads (Wheat germ agglutinin SPA beads from Amersham / Pharmacia, Freiburg, Germany) in a total volume of 250 .mu.l incubated for 90 minutes at room temperature. The incubation buffer used was 50 mmol / l Tris-HCl supplemented with 0.05% by weight sodium azide and with 0.06% by weight bovine serum albumin. To determine the unspecific binding an additional 25 .mu.mol / l naloxone was added. After the ninety-minute incubation period, the microtiter plates were centrifuged for 20 minutes at 1000 g and the radioactivity in a β-counter (Microbeta-Trilux, PerkinElmer Wallac, Freiburg, Germany) measured. The percentage displacement of the radioactive ligand from its binding to the human μ-opiate receptor at a concentration of the test substances of 1 .mu.mol / l was determined and expressed as a percentage inhibition (% inhibition) of the specific binding. In part, starting from the percentage displacement by different concentrations of the compounds of the general formula I to be tested, IC ₅₀ inhibitory concentrations were calculated, which cause a 50% displacement of the radioactive ligand. By conversion using the Cheng-Prusoff relationship, Ki values were obtained for the test substances.

The K _i values of the example compounds are summarized in the following table. substance K _i (ORL1) K _i (μ-OR) Ratio ORL1: μ ¹ classification B1 (fentanyl) 1600 nM 7.9 nM - μ agonist B2 (Sufentanil) 145 nM 0.8nM - μ agonist B3 (morphine) > 1 μM 9 nM - μ agonist B4 (oxycodone) > 10 μM 130 nM - μ agonist B5 (buprenorphine) 36 nM 0.3 nM - Opiold agonist (weak ORL1 component) B6 (hydromorphone) > 10 μM 4 nM - μ agonist B7 (L-methadone) > 1 μM 7nM - μ agonist B8 70 nM 2.4nM 0.03 (1:30) μ agonist, weak ORL1 agonist A1 14 nM 1.8nM 0.1 (1:10) gem. ORL1 / μ agonist A2 1.7nM 0.4nM 0.25 (1: 4) gem. ORL1 / μ agonist A3 0.3 nM 0.1 nM 0.3 (1: 3) gem. ORL1 / μ agonist A4 2nM 1nM 0.5 (1: 2) gem. ORL1 / μ agonist A5 2nM 1nM 0.5 (1: 2) gem. ORL1 / μ agonist A6 1nM 1nM 1 (1: 1) gem. ORL1 / μ agonist A7 0.4nM 0.3nM 1 (1: 1) gem. ORL1 / μ agonist A8 0.5 1.3nM 2 (2: 1) gem. ORL1 / μ agonist A9 0.5nM 1nM 2 (2: 1) gem. ORL1 / μ agonist A10 0.2nM 0.5nM 2 (2: 1) gem. ORL1 / μ agonist A11 1nM 23 nM 20 (20: 1) ORL1 / μ agonist comparatively weak μ component B9 0.4nM 55 nM 140 (140: 1) ORL1 agonist; comparatively weak μ component B10 (nociceptin) 0.3nM ~ 250 nM 800: 1 ORL1 agonist; endogenous ligand ¹ Definition: 1 / [K _{i (ORL1)} / K _{i (μ)} ]

Comparison of analgesic efficacy (as ED50,% MPE) in the acute pain model (tail-flick, rat / mouse) and in

Neuropathic pain models (Chung, Rat, Bennett, rat / mouse):

Analgesia test in the tail-flick test on the mouse

The analgesic efficacy of the test compound was determined in the mouse jet tail-flick test according to the method of D'Amour and Smith (J. Pharm. Exp. Ther. 72 74 79 (1941 For this purpose, NMRI mice weighing between 20-24 g were used. The animals were individually placed in special test cages and the tail base a focused heat beam of an electric lamp (tail-flick Type 55/12 / 10.fl, Labtec, Dr. Ing. Hess) suspended. The lamp intensity was adjusted so that the time from switching on the lamp to the sudden winceing of the tail (pain latency) in untreated animals was 2.5-5 seconds. Before giving a test compound, the animals were pretested twice within 30 minutes and the mean of these measurements was calculated as the pretest mean. The pain measurement was carried out at 20, 40 and 60 minutes after intravenous administration. The analgesic effect was determined as an increase in pain latency (% MPE) according to the following formula: $$\left[\left({\mathrm{T}}_{\mathrm{1}}\mathrm{-}{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="imgf0005.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathrm{0}}\right)\mathrm{/}\left({\mathrm{T}}_{\mathrm{2}}\mathrm{-}{\mathrm{T}}_{\mathrm{0}}\right)\right]\mathrm{x}\mathrm{100}$$

The T _{0 is} the latency time before and T _{1 is} the latency after substance application, T ₂ is the maximum exposure time (12 sec).

To determine the dose-dependency, the test compound was administered in 3-5 logarithmically increasing doses, which included the threshold and maximum effective dose, and the ED ₅₀ values were determined by means of the regression analysis. The ED ₅₀ calculation was carried out at the maximum of action 20 minutes after intravenous administration of the substance.

Analgesia test in the rat tail-flick test

The analgesic efficacy of the test compounds was determined in the jet-tail (tail-flick) test on the rat by the method of D'Amour and Smith (J. Pharm. Exp. Ther. 72, 74, 79 (1941 ). For this purpose, female Sprague Dawley were used with a weight between 134 and 189 g. The animals were individually placed in special test cages and the tail base exposed to a focused heat beam of a lamp (Tail-flick type 50/08 / 1.bc, Labtec, Dr. Hess). The lamp intensity was adjusted so that the time from switching on the lamp to the sudden winceing of the tail (pain latency) in untreated animals was 2.5-5 seconds. Prior to administration of a test compound, the animals were pretested twice within 30 minutes and the mean of these measurements calculated as the pretest mean. The pain was measured 20, 40 and 60 minutes after intravenous administration. The analgesic effect was determined as an increase in pain latency (% MPE) according to the following formula: $$\left[\left({\mathrm{T}}_{\mathrm{1}}\mathrm{-}{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="imgf0005.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathrm{0}}\right)\mathrm{/}\left({\mathrm{T}}_{\mathrm{2}}\mathrm{-}{\mathrm{T}}_{\mathrm{0}}\right)\right]\mathrm{x}\mathrm{100}$$

The T _{0 is} the latency before and T ₁ the latency after substance application, T ₂ is the maximum exposure time (12 sec).

To determine the dose-dependency, the respective test compound was administered in 3 to 5 logarithmically increasing doses, which in each case included the threshold and the maximum effective dose, and the ED ₅₀ values were determined by means of the regression analysis. The ED ₅₀ calculation was carried out in the active maximum, 20 minutes after intravenous administration of the substance.

Tail-fllck with reduced jet intensity in the rat

The modulatory efficacy of the test substances on acute, noxious thermal stimuli was measured in the rat jet tail-flick test according to the method of D'Amour and Smith (J. Pharm. Exp. Ther. 72, 74, 79 (1941 For this purpose, male Sprague-Dawley rats (breeder Janvier, Le Genest St. Isle, France) weighing between 200-250 g were used. The animals were individually placed in special test compartments and the tail base exposed to a focused beam of an analgesic meter (Model 2011, Rhema Labortechnik, Hofheim, Germany). The group size was 10 animals. The focal jet intensity was adjusted so that the time from switching on the burning jet to the sudden pulling away of the tail (Wegziehlatenz) in untreated animals was about 12-13 seconds. Before the administration of a substance according to the invention, the withdrawal latency was determined twice at intervals of five minutes and the mean value was defined as the control latency. The measurement of the latency of the tail was first carried out 10 minutes after intravenous administration of the substance. After the antinociceptive effect subsided (after 2-4 hours), measurements were taken at intervals of 30 minutes to a maximum of 6.5 hours after substance administration. The anti- or pronociceptive effect was determined as an increase or decrease in the withdrawal latency time according to the following formula: $$\left(\%\mathrm{MPE}\right)=\left[\left({\mathrm{T}}_{\mathrm{1}}\mathrm{-}{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="imgf0005.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathrm{0}}\right)\mathrm{/}\left({\mathrm{T}}_{\mathrm{2}}\mathrm{-}{\mathrm{T}}_{\mathrm{0}}\right)\right]\mathrm{x}\mathrm{100}$$

T ₀ : control latency before substance application, T ₁ : latency after substance application, T ₂ : maximum exposure time of the burning jet (30 seconds), MPE: maximum possible effect.

By means of repeated measures ANOVA was tested for statistically significant differences between substance and vehicle group. The significance level was set to ≤ 0.05.

Chung model: Mononeuropathy pain after spinal nerve ligation

Animals: Male Sprague Dawley rats (140-160g) from a commercial breeder (Janvier, Genest St. Isle, France) were kept under a 12: 12h light-dark rhythm. The animals were kept ad libitum with food and tap water. Between the delivery of the animals and the operation a break of one week was kept. The animals were repeatedly tested after surgery for a period of 4-5 weeks, with a washout of at least one week was observed.

Model Description: Under pentobarbital anesthesia (Narcoren ^®, 60 mg / kg ip, Merial GmbH, Hallbergmoos, Germany), were the left L5, exposed L6 spinal nerves, By a piece of paravertebral muscle and a portion of the left spinal process of the L5 lumbar vertebral body away were. Spinal nerves L5 and L6 were gently isolated and ligated with a solid ligature (NC-silk black, USP 5/0, metric 1, Braun Melsungen AG, Melsungen, Deutschtand) (Kim and Chung 1992). After ligature, muscle and adjacent tissues were sutured and the wound closed with metal clips.

After a week of recovery time, the animals were placed in cages with a wire bottom to measure mechanical allodynia. On an ipsi- and / or contralateral hind paw, the withdrawal threshold was determined by means of an electronic von Frey filament (Somedic AB, Malmö, Sweden). The median of five stimulations gave one measurement point. The animals were tested 30 min before and at various times after application of test substance or vehicle solution. The data were determined as% maximum possible effect (% MPE) from the pretests of the individual animals (= 0% MPE) and the test values of an independent sham control group (= 100% MPE). Alternatively, the withdrawal thresholds were displayed in grams.

Statistical evaluation: ED ₅₀ values and 95% confidence intervals were determined by semilogarithmic regression analysis at the time of maximum effect. Data were analyzed by repeated measures analysis of variance and Bonferroni post hoc analysis. The group size was usually n = 10.

References: Kim, SH and Chung, JM, An experimental model for peripheral neuropathy produced by segmental spinal nerve ligation in the rat, Pain, 50 (1992) 355-363 ,

Bennett Model: Neuropathic pain in the mouse or rat

The study of efficacy in neuropathic pain was performed in the Bennett model (chronic constriction injury; Bennett and Xie, 1988, Pain 33: 87-107 )

Sprague-Dawley rats weighing 140-160g are treated with four loose ligatures of the right nervus ischiaticus under Narcoren's general anesthesia. NMRI mice weighing 16-18g are treated with three loose ligatures of the right nervus ischiaticus under Ketavet-Rompun anesthesia. The animals develop hypersensitivity to the paw innervated by the damaged nerve, which is quantified after a recovery period of one week for about four weeks using a 4 ° C cold metal plate (cold allodynia). The animals are kept for a period of 2 min. observed on this plate and the number of pull-out reactions of the injured paw is measured. Based on the pretreatment value before administration of the substance, the substance activity is determined over a period of one hour at four time points (for example 15, 30, 45, 60 minutes after application) and the resulting area under the curve (AUC) as well as the inhibition of the cold. Allodynia expressed as a percentage of the individual measuring points Effect on the vehicle control (AUC) or on the initial value (single measuring points). The group size is n = 10, the significance of an anti-allodynic effect (* = p <0.05) is determined by means of a repeated measures analysis of variance and a Bonferroni post hoc analysis.

Vincristine-induced polyneuropathy

The model is described in the literature ( KO Aley, DB Reichling, JD Levine, Neuroscience 1996, 73, 259-265 ).

Diabetic polyneuropathy pain

The model is described in the literature ( SC Ahlgren, JD Levine, Neuroscience 1993, 52, 1049-1055 ).

Relative potency enhancement in neuropathic pain models substance Ratio ORL1 / μ ED ₅₀ acute ED ₅₀ chron. Application route Factor gain enhancement B3 (morphine) <1: 100 1.1 mg / kg ¹ 3.7 mg / kg ⁴ iv 0.3x B3 (morphine) <1: 100 1.1 mg / kg ¹ 1.3 mg / kg ⁵ iv 0.8x B3 (morphine) <1: 100 2 μg / animal ³ ~10 μg / animal ⁴ i.th. 0.5x B4 (oxycodone) <1: 100 360 μg / kg ¹ 2170 μg / kg ⁴ iv 0.2x 84 (oxycodone) <1: 100 360 μg / kg ¹ 900 μg / kg ⁵ iv 0.4x B4 (oxycodone) <1: 100 670 μg / kg ¹ 2520 μg / kg ⁴ ip 0.3x 84 (oxycodone) <1: 100 670 μg / kg 1290 μg / kg ⁵ ip 0.5x B6 (hydromorphone) <1: 100 150 μg / kg ¹ 220 μg / kg ⁴ iv 0.7x B7 (L-methadone) <1: 100 210 μg / kg ¹ 490 μg / kg ⁴ iv 0.4x 85 (buprenorphine) <1: 100 17 μg / kg ¹ 55 μg / kg ⁴ iv 0.3x B1 (fentanyl) <1: 100 10 μg / kg ¹ 11 μg / kg ⁴ iv 0.9x B1 (fentanyl) <1: 100 43 μg / kg ¹ 230 μg / kg ⁴ ip 0.2x B8 1:30 330 μg / kg ¹ 363 μg / kg ⁴ iv 0.9x A1 1:10 110 μg / kg ¹ 9 μg / kg ⁴ iv 12x A1 1:10 110 μg / kg ¹ 11 μg / kg ⁵ iv 10x A4 1: 2 7 μg / kg ¹ 1 μg / kg ⁴ iv 7x A4 1: 2 7 μg / kg ¹ 1 μg / kg ⁵ iv 7x A5 1: 2 71 μg / kg ¹ 8 μg / kg ⁴ iv 8x A5 1: 2 71 μg / kg ¹ 10 μg / kg ⁵ iv 7x A6 1: 1 9 μg / kg ¹ 4 μg / kg ⁴ iv 2.5x A6 1: 1 9 μg / kg ¹ 1 μg / kg ⁵ iv 9 x A7 1: 1 2 μg / kg ¹ 1 μg / kg ⁴ iv 2 x A9 2: 1 2 μg / kg ¹ 0.8 μg / kg ⁴ iv 2.5x A11 20: 1 > 10 μg / animal 2 0.2 μg / animal ⁸ i.th. > 50x A11 420 μg / kg ² no data iv ¹ ) tail-flick model, rat
² ) tail-flick model, mouse
³ ) Soft tail-flick model, rat
⁴ ) Chung model, rat
⁵ ) Bennett model, rat
⁸ ) Bennett-Modlell, mouse

For graphical presentation, the ED ₅₀ value from the tail-flick test and from the neuropathic pain models were normalized to the ED ₅₀ value in the tail-flick test to represent the relation of the respective half-maximal doses (see Figures 1 and 2) ).

Antagonization of the μ and the ORL1 component in the Chung model

In antagonization experiments a partial antagonism with naloxone (μ-OR) and B11 (ORL1-R) was shown in each case. The data prove that both components contribute to analgesia (s. Figure 3 ).

Even with a high very high dosage of B11, d. H. with complete blockage of the ORL1 mechanism of action, analgesic efficacy of A4 remains.

Figure 4 shows that by antagonizing the μ- or the ORL1 component of A6, A5 and A1 with naloxone or B11 in each case an analgesic effect of the non-antagonized component remains.

Separation of anti-nociceptive and anti-allodynic effect in neuropathic animals: Comparison of A4 and morphine in neuropathic animals

In the Chung model, it is possible to differentiate between antinociceptive (contralateral) and antiallodynic (ipsilateral) effects by comparative testing of the pain reaction on the ipsi and contratateral paws.

For morphine, a purely antiallodynic effect could only be achieved after administration of 1 mg / kg iv. to be watched. The maximum effectiveness is 29% MPE. At the next higher dose (2.15 mg / kg iv), there is already a marked antinociceptive effect (Figures 5, 5a).

In contrast, the maximum, purely antiallodynic effect of A4 is 56% MPE. This is iv at a test dose of 1 μg / kg. achieved (Figures 6, 6a).

Conclusion: The ORL1 component achieves a significantly stronger antiallodynic effect than pure μ opioids.

Direct comparison of A4 and morphine in naive and neuropathic animals

In order to exclude a possible influence of "pain quality" (tail-flick, nociceptive irritation vs. chung, tactile allodynia) in comparing the different efficacy in acute pain and neuropathy pain, A4 and morphine were compared in animals with spinal nerve ligature (Chung model) and sham-operated Tested animals. As a pain model, the tail-flick was used in all cases. The direct comparison shows that after the development of neuropathy, the efficacy of morphine decreases (which corresponds to the clinical situation), while it increases for A4 (see Figures 7 and 8).

With comparable effectiveness of both substances in acute pain (see above), the antiallodynic activity of A4 is about a factor of 10 higher than that of fentanyl.

Comparison of cytostatic-induced polyneuropathy pain and diabetic induced polyneuropathy pain

A4 shows significant efficacy in vincristine-induced polyneuropathic pain in rats at a dosage of 1 μg / kg ( Fig. 24 ). At a dosage of 0.464 mg / kg, no significant efficacy is observed (14.7 ± 10.2% MPE). In diabetic-induced neuropathic pain, on the other hand, a significant efficacy is already observed for the lowest dose tested (0.316 μg / kg) ( Fig. 26 ). In this dose range no antinociceptive effect is observed. The clinically used comparison substances morphine and pregabalin show efficacy in diabetic polyneuropathic pain only in one dose range, in which also an antinociceptive effect is observed ( Fig. 27 . 28 ).

Enhancement of inflammatory pain by mixed ORL1 / μ agonists a) Slngle Motor Unit Derivatives In Spinalized Rats. Comparison of naive animals and animals after carrageenan-induced inflammation.

The model is described in the uterus ( Herrero & Headley, 1996, Br J Pharmacol 118, 968-972 ).
24 h after induction of inflammation (100 μl carrageenan, 1%, intraplantar), the anti-nociceptive effect of A4 (measured as inhibition of SMU activity after mechanical (pinch) or electrical (wind-up) stimulation) is significantly increased (s Figures 10 and 10a). In contrast, the antinociceptive effect of morphine does not change after inflammation (see Figures 11 and 11a).

In addition, in this model, an enhancement of activity after inflammation induction was also shown for A11.

CFA-induced hyperalgesia Complete Freund's adjuvant (CFA) induced hyperalgesia in the rat

HA Vorwert = Wegziehschwelle contralateral - Wegziehschwelle ipsilateral vor Substanzgabe
HA Messwert = Wegziehschwelle contralateral - Wegziehschwelle ipsilateral nach Substanzgabe $$\%\mathrm{MPE}=\left[\left(\mathrm{WSs\; ipsi}-\mathrm{WSo\; ipsi}\right)/\mathrm{WSo\; contra}-\mathrm{WSo\; ipsi}\right]x100$$

WSo contra = Wegziehschwelle der contralateralen unbehandelten Pfote
WSo ipsi = Wegziehschwelle der ipsilateralen unbehandelten Pfote
WSs ipsi = Wegziehschwelle der ipsilateralen behandelten Pfote nach Substanzgabe
MPE%: Prozent des maximal möglichen Effekts; der maximale mögliche Effekt ist als die Wegziehschwelle der contralateralen unbehandelten Pfote definiertCFA-induced hyperalgesia is an animal model of chronic inflammatory pain. Male Sprague-Dawley rats (150-180g) receive 100 μl of heat-killed and dried mycobacteria (Mycobacterium tuberculosis; H37 Ra) in a mixture of paraffin oil and mannide monooleate as emulsifier (Complete Freund's adjuvant, CFA) injected subplantar (Dose 1 mg / ml). One day after the CFA injection tactile hyperalgesia is checked with the help of an electronic device from Frey Haar (Somedic Sales AB, Hörby, Sweden). For this, the animals are placed in a plastic box with a grid floor, which allows free access to both hind feet. With Frey's filament, the paw is stimulated subplantar. To quantify the sensitivity of both the ipsials and the (untreated) contralateral paw to the mechanical stimulus, the paw withdrawal threshold is given in grams of the applied pressure. Per paw, the stimulation is repeated 4x at a time interval of 30 seconds each. The median is formed from the four measured values. The withdrawal threshold of the ipsi and contralateral paw is determined at various times after CFA injection (1h, 3h, 1st, 4th), before (= pre-value) and at different time points after substance administration (measured value). A control group of solvents is administered is carried. The efficacy of a substance is calculated as% inhibition of hyperalgesia and further as MPE% as follows $$\%\mathrm{Inhibition\; of\; HA}=\left(1-\mathrm{HA\; reading}/\mathrm{<figure-callout\; id="100"\; label="HA\; pre-value\; x"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">HA\; pre-value\; </figure-callout>}\right)x100$$

HA Prevalence = withdrawal threshold contralateral - withdrawal threshold ipsilateral before substance administration
HA reading = withdrawal threshold contralateral - withdrawal threshold ipsilateral after substance administration $$\%\mathrm{MPE}=\left[\left(\mathrm{WSs\; ipsi}-\mathrm{WSo\; ipsi}\right)/\mathrm{WSo\; contra}-\mathrm{<figure-callout\; id="100"\; label="WSo\; ipsi\; x"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">WSo\; ipsi\; </figure-callout>}\right]x100$$

WSo contra = withdrawal threshold of the contralateral untreated paw
WSo ipsi = withdrawal threshold of the ipsilateral untreated paw
WSs ipsi = withdrawal threshold of the ipsilateral treated paw after substance administration
MPE%: Percent of the maximum possible effect; the maximum possible effect is defined as the withdrawal threshold of the contralateral untreated paw

In total, 10 rats are used per test animal group (substance and control). The mean ± SEM is calculated from the medians of the individual animals. The significance calculation is carried out by means of two-factor ANOVA for repeated measurements. The significance of the interaction substance application (treatment), time, time * treatment is analyzed using Wilks' Lambda statistics. in case of a Significant treatment effect is a Fischer test followed by a post hoc Dunnett test.

While morphine tends to show a slight decrease in antihyperalgesic or antinociceptive activity over the study period, the antihyperalgesic and antinociceptive effects of A4 increase over 24 h. The effect is stable for at least 4 days (see Figures 12, 12a).

Mustard oil induced visceral inflammatory pain in the mouse

Male NMRI mice (body weight 20-35g) are habituated on a grid in plexiglas cages (14.5 x 14.5 cm, height 10 cm) for about thirty minutes.

The behavior of the mice on ten mechanical stimulation by means of Frey filaments (1, 4, 8, 16, 32 mN) on the abdominal wall is taken as a precondition. The behavior is determined either by the sum of the number of nozifensiven reactions or the quality of these nozifensiven reactions and their weighting by multiplication of the number of reactions with the appropriate factor (factor 1: slight lifting of the abdomen, licking at the stimulus, leaving, factor 2 : Walking of the hind paws, easy jumping away, twitching of the hind paws, jerky, strong licking of the stimulus site, factor 3: jumping away, vocalization) and subsequent summation analysis.

Subsequently, the application of test substance or vehicle depending on the kinetic property of the substance with a suitable mode of administration at a suitable time before the administration of mustard oil. The group size is usually n = 7.

Acute colitis is induced by rectal administration of 50μl mustard oil (3.5% in PEG200). Two to twelve minutes after mustard oil administration, the animals show spontaneous visceral pain behavior, which is observed. The number of reactions is multiplied by the corresponding factor (Factor 1: licking the abdominal wall, factor 2: stretching, pressing the abdomen against the floor, bridging, contraction of the abdomen, backward movement or contraction of the flank muscles) and then the sum forming the spontaneous represents visceral pain score. A group of animals receives a rectal application of 50μl PEG200 instead of mustard oil.

Twenty to forty minutes after the mustard oil administration, the animals' behaviors are monitored again for ten mechanical stimulations using Frey filaments (1, 4, 8, 16, 32 mN) on the abdominal wall and quantified as described above. The transferred mechanical allodynia is hereby determined from the sum of the reactions to the stimulation with that of Frey filament of strength 1mN. The transferred mechanical hyperalgesia is determined from the sum of the weighted reactions to the stimulation with that of Frey filament of strength 16mN.

The effect of the test substance compared to vehicle is described by 1. inhibition of spontaneous visceral pain behavior, 2. inhibition of transmitted mechanical allodynia and 3. inhibition of transmitted mechanical hyperalgesia.

Data is analyzed by repeated-factor multi-factorial analysis of variance, and if there is a significant effect of the test substance (P <0.05), the individual data are tested for significance using Bonferroni post hoc analysis. For dose response curves, ED ₅₀ values describing the dose with the half-maximal effect can be determined by linear regression analysis. (to Christoph et al., 2005, Eur. J. Pharmacol. 507: 87-98 ).

Comparative testing of A4 and fentanyl in a model of transmitted allodynia and hyperalgesia in mice after mustard oil induced non-neurogenic visceral inflammation showed a significantly increased efficacy of mixed ORL1 / μ for all three pain parameters, but especially for allodynia and hyperalgesia Agonists compared to the pure μ opioid.

Transmitted allodynia

substance Ratio ORL1 / μ ED ₅₀ acute ED ₅₀ visceral pain Factor gain enhancement B1 (fentanyl) <1: 100 30 μg / kg iv ¹ 47 μg / kg i.v. 0.6x A4 1: 2 19 μg / kg iv ¹ 2.8 μg / kg i.v. 7x ¹ ) tail-flick, mouse

Transmitted hyperalgesia

substance Ratio ORL1 / μ ED ₅₀ acute ED ₅₀ visceral pain Factor gain enhancement B1 (fentanyl) <1: 100 30 μg / kg iv ¹ 42 μg / kg i.v. 0.7x A4 1: 2 19 μg / kg iv ¹ 3.0 μg / kg i.v. 6 x ¹ ) tail-flick, mouse

The analgesic efficacy of A4 with respect to the two tested pain parameters is about a factor of 6 to 7 higher than in acute pain. In contrast, the analgesic efficacy of fentanyl in visceral inflammatory pain is less than in acute pain.

Effect in acute pain models

The mixed ORL1 / μ agonists with an ORL1: μ ratio of 1:10 to 30: 1 show full potency in acute pain models (tail-flick, mouse, and rat). The results in the tail-flick are shown in Table 3 (see above). The effect is shown using examples between ORL1: μ 1:10 to 20: 1. According to their binding affinity to μ-OR, the potency is in the range of the standard opioids (sufentanil, fentanyl, buprenorphine, oxycodone, morphine) (s. Figure 13 ).

Opioid-induced hyperalgesia

The chronic administration of opioids leads to hyperalgesia in patients with pain (cf. Chu et al. 2006, J. Pain 7: 43-48 ). A similar phenomenon also occurs after acute administration in the withdrawal situation ( Angst et al. 2003, Pain 106: 49-57 ). In the animal model, pure μ-opioids induce transient hyperalgesia after acute administration (opioid-induced hyperalgesia, A qualitative systematic review.

Angst and Clark, Anesthesiology 2006; 104: 570-87 ), which can be detected in the soft tail-flick model as a transient "pronociceptive" phase, for example. Corresponding findings are described in literature. This opioid-induced hyperalgesia was diagnosed with the help of a modified soft tail-flick model (25% firing intensity) for pure μ-opioids (fentanyl and morphine). In contrast, transient hyperalgesia was not observed following acute administration of mixed ORL1 / μ agonists (A4 and A10) (Figures 14-14c).

Determination of physical dependence

Testing was performed in two models: naloxone-induced deprivation in mice and spontaneous withdrawal in rats. In both models, withdrawal symptoms were significantly reduced in mixed ORL1 / μ agonists versus pure μ agonists.

Jumping test on the mouse: attempt to determine the physical dependence (Saelens JK, Arch Int Pharmacodyn 190: 213 218, 1971)

The test substances are administered intraperitoneally for a total of 7x for two days. 5 applications are performed on the first day at 9:00, 10:00, 11:00, 13:00 and 15:00 and on the second day at 9:00 and 11:00 , The first 3 applications are given in ascending doses (dosing scheme) and then further in the dosing of the third. The withdrawal is precipitated 2 hours after the last administration of naloxone 30 mg / kg (i.p.). Immediately thereafter, the animals are placed individually in transparent observation boxes (height 40 cm, diameter 15 cm) and the jump reactions are counted over 15 minutes in 5-minute periods. Morphine is included in one dose as a comparison / standard.

The quantification of the withdrawal takes place over the number of jumps 0 to 10 min. after naloxone application. The number of animals per group with more than 10 hops / 10 min is determined and documented as "% positive animals". In addition, the average jump frequency in the group is calculated. 12 animals are used per group.

The μ-agonists B1-B4 induce a significant withdrawal jump. The μ-agonist B7 (L-methadone, levomethadone, Figure 15 ) induces a reduced but significant withdrawal jump compared to B1-B4. B8 and A1 also trigger a significant withdrawal jump in this test (Figures 15a and 15b). By contrast, A9 only triggers a slight withdrawal jump, that at higher doses is completely suppressed ( Figure 15c ). After administration of A4 or A7 hardly or no significant withdrawal jump occurs (Figures 15d and 15e).

Spontaneous withdrawal from the rat:

• Phase 1 (chronische Behandlungsphase): Ratten werden über 3 Wochen mit der Testsubstanz behandelt. Die Applikation wurde 2 oder 3x täglich (je nach Wirkdauer der Testsubstanz) intraperitoneal vorgenommen.
• Phase 2 (Spontanentzug): Anschließend erfolgte ein Spontanentzug und eine behandlungsfreie Periode (Phase 3) von einer Woche. Anschließend erhielten die Tiere eine weitere Woche die Testsubstanz (Phase 4).
• Phase 5 (Naloxon-induzierter Entzug): Dann wurde mit Naloxon (10 mg/kg i.p.) ein Entzug eingeleitet.

The opiate spontaneous withdrawal study was conducted in 5 phases.

• Phase 1 (chronic treatment phase ): Rats are treated with the test substance for 3 weeks. The application was made intraperitoneally 2 or 3 times a day (depending on the duration of action of the test substance).
• Phase 2 (spontaneous withdrawal): This was followed by a spontaneous withdrawal and a treatment-free period ( phase 3) of one week. The animals then received the test substance for another week ( phase 4 ).
• Phase 5 (naloxone-induced withdrawal): withdrawal was then initiated with naloxone (10 mg / kg ip).

• Beurteilung der (6) Hauptsymptome im Entzug: Tremor, Salivation, Writhing, wet dog shaking, Hopsen und Springen, Zähneknirschen
• 0= nicht vorhanden, 1=leicht, 2= schwer
• maximaler Score = 12
• Als Referenzsubstanz wurde Morphin mitgeführt

Measurement parameters in the withdrawal: animal weights, behavioral parameters:

• Assessment of (6) main symptoms of withdrawal: tremor, salivation, writhing, wet dog shaking, jumping and jumping, teeth grinding
• 0 = not available, 1 = easy, 2 = difficult
• maximum score = 12
• The reference substance was morphine

The study on Opiate spontaneous withdrawal was created after literature description Jaffe JH (1990) Drug addiction and drug abuse. In: Goodman Gilman A, Rall TW, Nies AS, Taylor P (eds.) The pharmacological basis of therapeutics. New York, Pergamon Press: 522-573 ,

Bläsig J, Herz A, Reinhold K, Zieglgänsberger S (1973) Development of physical dependence on morphine in relation to time and dosage and quantification of the precipitated withdrawal syndrome. Psychopharmacology 33: 19-38 ,

The spontaneous withdrawal results are shown in Figure 16

A4, A7 and A9 show in the Jumping test no or at least in comparison to morphine significantly reduced withdrawal symptoms A1 (ORL1: μ 1:10) causes withdrawal in withdrawal, but in spontaneous withdrawal is not significant To watch weight loss. With prior administration of morphine, however, the body weight of the rat drops by about 10%. A1 is therefore characterized by a reduced dependence potential compared to morphine.

Reduction of μ-mediated respiratory depression by an ORL1-dependent mechanism Acute μ-mediated respiratory depression in the rat Method for pCO ₂ - and PO ₂ - Measurement in the rat (blood gas analysis)

The respiratory depressant effect of test substances is investigated after intravenous administration to instrumented, awake rats. The test parameter is the change in carbon dioxide partial pressure (pCO ₂ ) and oxygen partial pressure (pO ₂ ) in the arterial blood after substance administration.

Experimental animals : male rats, Sprague-Dawley; Weight: 250-275g Test Preparation: At least 6 days prior to the test substance application, the rats are implanted with a PP catheter into the femoral artery and the jugular vein under pentobarbital anesthesia. The catheters are filled with heparin solution (4000 IU) and closed with a wire pen.

Experimental procedure: The substance or vehicle application takes place via the venous catheter. Before the substance or vehicle application and at defined times after substance or vehicle application, the arterial catheter is opened in each case and rinsed with about 500 μl heparin solution. Then, about 100 μl of blood is withdrawn from the catheter and taken up by means of a heparinized glass capillary. The catheter is rinsed again with heparin solution and resealed. The arterial blood is measured immediately with the help of a blood gas analyzer (ABL 5, Radiometer GmbH, Willich, Germany).

After a minimum washout period of one week, the animals can be re-tested.

Experiment evaluation: The blood gas analyzer automatically provides the values for pCO ₂ and pO _{2 of} the blood in mmHg. Substance effects on the partial pressure are calculated as percentage changes compared to the initial values without substance or vehicle. For the statistical evaluation, the measured values after substance administration and the simultaneous measured values after vehicle application by means of one-factor Analysis of variance. In case of a significant Substance effect, a post hoc Dunnett test is performed.

In pure μ-opioids (here fentanyl and oxycodone, Figures 17 and 17a) occurs at the time of analgesic maximum efficacy due to the μ-induced respiratory depression to a significant increase in arterial pCO ₂ . At a 90-100% effective dose, the pCO ₂ value increases by more than 50%.

In comparison, the pCO ₂ value was determined on mixed ORL1 / μ agonists. Even at doses that are maximally effective analgesically for several hours, the arterial pCO2 only increases by approximately 20-30% after administration of the mixed ORL1 / μ agonists (Figures 17b-17e).

The observed effect was investigated using the example of A4 for its cause. B11 (2.15 mg / kg) was administered together with A4 at time 0 (i.v.) in order to antagonize the ORL1 component and to observe only the μ effect. In another experiment, 20 minutes after administration of A4 + B11, naloxone (1 mg / kg i.v.) was added to test whether the resulting respiratory depressant effect is solely a μ-mediated effect.

The result shows that the reduced respiratory depression of A4 compared to pure μ-opioids is clearly due to the ORL1 component ( Figure 18 ). Thus, the pCO ₂ value after antagonizing with B11 increases to a value which is typical for pure μ-opioids. If naloxone is given after the maximum pCO ₂ increase has been reached, the value drops again. This proves that μ-mediated respiratory depression is reduced by the ORL1 component.

safety distance

The safety distances for various mixed ORL1 / μ agonists and pure μ agonists represented as the distance between threshold dose (ED ₁₀₎ for an increase in arterial pCO ₂ and the half-maximum effective in the Chung model dose (ED ₅₀₎ are in Figure 20 clarified.

The threshold dose (ED ₁₀ ) for an increase in the arterial pCO ₂ in A1, A4, A5 and A7 is about a factor of 3 to 20 above the half-maximal effective dose (ED ₅₀ ) in the Chung model, while the threshold dose for the μ Agonists B1, B3, and 85 in the range of the half-maximal effective dosage (ED ₅₀ ) in the Chung model or even significantly lower for B4. The safety margins between effect and side effect are therefore significantly increased for the mixed ORL1 / μ agonists compared to the μ agonists.

Psychic dependence / addiction

To study the place preference see: Tzschentke, TM, Bruckmann, W., and Friderichs, F. (2002) Lack of sensitization during place conditioning in rats is consistent with the low abuse potential of tramadol. Neuroscience Letters 329, 25-28 ,

A4, A6 and A7 induce site preference, but in a dose range lower by up to a factor of 100 compared to pure μ antagonists B1 and B3-B5 ( Figure 21 ).

The example of A7 shows that the reduced space preference is due to the ORL1 component. First, the place preference was tested at different dosages ( Figure 22 )

After administration of A7, B11 was antagonized. It could be shown that, after blocking the ORL1 component, the threshold for induction of a place preference is shifted to lower dosage ( Figure 23 ). This finding demonstrates that the ORL1 component attenuates μ-OR mediated site conditioning.

Claims (6)

1. Compounds which exhibit an affinity for the µ-opioid receptor of at least 100 nM (K_i value, human) and an affinity for the ORL-1 receptor, wherein the ratio between the affinities ORL1/µ defined as 1/[K_¡(ORL1)/K_i(µ)] is from 0.1 to 30, and which are the spirocyclic cyclohexane derivates of the general formula (I)

   

   in which

   R¹ and R² mutually independently denote H or CH₃, wherein R¹ and R² do not simultaneously mean H;

   R³ denotes phenyl, benzyl or heteroaryl, in each case unsubstituted or mono- or polysubstituted with F, Cl, OH, CN or OCH₃;

   W denotes NR⁴, O or S

   and

   R⁴ denotes H; C_1-5 alkyl; phenyl; phenyl, attached via a C_1-3 alkyl group; COR¹²; SO₂R¹²,

   wherein R¹² means H; C_1-7 alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted with OH, F or GOOC_1-4 alkyl; C_4-6 cycloalkyl; aryl, or heteroaryl, unsubstituted or mono- or polysubstituted with F, Cl, Br, CF₃, OCH₃, C_1-4 alkyl, branched or unbranched, unsubstituted or substituted with F, Cl, CN, CF₃ OCH₃ or OH; or phenyl or heteroaryl, unsubstituted or mono- or polysubstituted with F, Cl, Br, CF₃, OCH₃, C_1-4 alkyl, branched or unbranched, unsubstituted or substituted with F, Cl, CN, CF₃, OCH₃ or OH, attached via saturated or unsaturated C_1-3 alkyl, or C_5-6 cycloalkyl attached via saturated or unsaturated C_1-3 alkyl; OR¹³; NR¹⁴R¹⁵;

   R⁵ denotes H; COOR¹³, CONR¹³, OR¹³; C_1-5alkyl, saturated or unsaturated, branched or unbranched, unsubstituted or mono- or polysubstituted with OH, F, CF₃ or CN;

   R⁶ denotes H;

   or R⁵ and R⁶ together mean (CH₂)_n with n = 2, 3, 4, 5 or 6, wherein individual hydrogen atoms may also be replaced by F, Cl, NO₂, CF₃, OH¹³, CN or C_1-5 alkyl:

   R⁷, R⁸, R⁹ and R¹⁰ mutually independently denote H, F, Cl, Br, NO₂, CF₃, OH, OCH₃, CN, COOR¹³, NR¹⁴R¹⁵; C_1-5 alkyl, heteroaryl, unsubstituted or mono- or polysubstituted with benzyl, CH₃, Cl, F, OCH₃ or OH;

   wherein R¹³ means H or C_1-5 alkyl;

   R¹⁴ and R¹⁵ mutually independently mean H or C_1-5 alkyl;

   X denotes O, S, SO, SO₂ or NR¹⁷;

   R¹⁷ denotes H; alkyl, saturated or unsaturated, branched or unbranched; COR¹² or SO₂R¹²,

   in the form of the pure diastereomers thereof, the racemates thereof, the pure enantiomers thereof, or in the form of mixtures of the stereoisomers in any desired mixing ratio; as bases or in the form of the salts thereof, in particular the physiologically acceptable salts, or salts of physiologically acceptable acids or cations;

   - for use in narcosis;

   - for use in the treatment of pain accompanying narcosis;

   - for use in the treatment of neuropathic pain selected from the group consisting of chronic neuropathic pain, polyneuropathic pain and polyneuropathic pain induced by cytostatics.
2. Compounds for use in the treatment of chronic neuropathic pain according to claim 1, which are used at a dosage which is lower by a factor of at least 2 than the dosage used against acute pain.
3. Compounds for use according to claim 2, which are used at a dosage which is lower by a factor of at least 5 than the dosage used against acute pain.
4. Compounds for use according to claim 1, selected from the group consisting of
   1,1-(3-methylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4b]indole hemicitrate;
   1,1-(3-methylamino-3-phenylpentamethylene)-1,3,4,9-tetrahydropyrano[3,4-b]indole hemicitrate;
   1,1-[3-dimethylamino-3-(3-thienyl)pentamethylene]-1,3,4,9-tetrahydropyrano[3,4-b]indole hemicitrate;
   1,1-(3-dimethylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4-b]indole hemicitrate;
   1,1-[3-methylamino-3-(2-thienyl)pentamethylene]-1,3,4,9-tétrahydropyrano[3,4-b]-6-fluoroindole citrate;
   1,1-[3-dimethylamino-3-(2-thienyl)pentamethylene]-1,3,4,9-tetrahydropyrano[3,4-b]-6-fluoroindole hemicitrate;
   1,1-[3-dimethylamino-3-(2-thienyl)pentamethylene]-1,3,4,9-tetrahydropyrano[3,4-b]indole citrate;
   1,1-[3-dimethylamino-3-(3-thienyl)pentamethylene]-1,3,4,9-tetrahydropyrano[3,4-b]-6-fluoroindole hemicitrate;
   1,1-(3-dimethylamino-3-phenylpentamethylene)-1,3,4,9-tetrahydropyrano[3,4-b]indole hemicitrate; and
   1,1-[3-methylamino-3-(2-thienyl)pentamethylene]-1,3,4,9-tetrahydropyrano[3,4-b]indole citrate.
5. 1,1-(3-methylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4b]indole in the form of a pure diastereomer or in the form of mixtures of the stereoisomers in any desired mixing ratio; as a base or in the form of a physiologically acceptable salt; for use in the treatment of neuropathic pain.
6. 1,1-(3-dimethylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4-b]indole in the form of a pure diastereomer or in the form of mixtures of the stereomers in any desired mixing ratio; as a base or in the form of a physiologically acceptable salt; for use in the treatment of neuropathic pain.

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